xref: /sqlite-3.40.0/src/main.c (revision 7aa3ebee)
1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code.  In place of
5 ** a legal notice, here is a blessing:
6 **
7 **    May you do good and not evil.
8 **    May you find forgiveness for yourself and forgive others.
9 **    May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** Main file for the SQLite library.  The routines in this file
13 ** implement the programmer interface to the library.  Routines in
14 ** other files are for internal use by SQLite and should not be
15 ** accessed by users of the library.
16 */
17 #include "sqliteInt.h"
18 
19 #ifdef SQLITE_ENABLE_FTS3
20 # include "fts3.h"
21 #endif
22 #ifdef SQLITE_ENABLE_RTREE
23 # include "rtree.h"
24 #endif
25 #ifdef SQLITE_ENABLE_ICU
26 # include "sqliteicu.h"
27 #endif
28 #ifdef SQLITE_ENABLE_JSON1
29 int sqlite3Json1Init(sqlite3*);
30 #endif
31 #ifdef SQLITE_ENABLE_FTS5
32 int sqlite3Fts5Init(sqlite3*);
33 #endif
34 
35 #ifndef SQLITE_AMALGAMATION
36 /* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
37 ** contains the text of SQLITE_VERSION macro.
38 */
39 const char sqlite3_version[] = SQLITE_VERSION;
40 #endif
41 
42 /* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
43 ** a pointer to the to the sqlite3_version[] string constant.
44 */
45 const char *sqlite3_libversion(void){ return sqlite3_version; }
46 
47 /* IMPLEMENTATION-OF: R-63124-39300 The sqlite3_sourceid() function returns a
48 ** pointer to a string constant whose value is the same as the
49 ** SQLITE_SOURCE_ID C preprocessor macro.
50 */
51 const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
52 
53 /* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
54 ** returns an integer equal to SQLITE_VERSION_NUMBER.
55 */
56 int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
57 
58 /* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
59 ** zero if and only if SQLite was compiled with mutexing code omitted due to
60 ** the SQLITE_THREADSAFE compile-time option being set to 0.
61 */
62 int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
63 
64 /*
65 ** When compiling the test fixture or with debugging enabled (on Win32),
66 ** this variable being set to non-zero will cause OSTRACE macros to emit
67 ** extra diagnostic information.
68 */
69 #ifdef SQLITE_HAVE_OS_TRACE
70 # ifndef SQLITE_DEBUG_OS_TRACE
71 #   define SQLITE_DEBUG_OS_TRACE 0
72 # endif
73   int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
74 #endif
75 
76 #if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
77 /*
78 ** If the following function pointer is not NULL and if
79 ** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
80 ** I/O active are written using this function.  These messages
81 ** are intended for debugging activity only.
82 */
83 SQLITE_API void (SQLITE_CDECL *sqlite3IoTrace)(const char*, ...) = 0;
84 #endif
85 
86 /*
87 ** If the following global variable points to a string which is the
88 ** name of a directory, then that directory will be used to store
89 ** temporary files.
90 **
91 ** See also the "PRAGMA temp_store_directory" SQL command.
92 */
93 char *sqlite3_temp_directory = 0;
94 
95 /*
96 ** If the following global variable points to a string which is the
97 ** name of a directory, then that directory will be used to store
98 ** all database files specified with a relative pathname.
99 **
100 ** See also the "PRAGMA data_store_directory" SQL command.
101 */
102 char *sqlite3_data_directory = 0;
103 
104 /*
105 ** Initialize SQLite.
106 **
107 ** This routine must be called to initialize the memory allocation,
108 ** VFS, and mutex subsystems prior to doing any serious work with
109 ** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
110 ** this routine will be called automatically by key routines such as
111 ** sqlite3_open().
112 **
113 ** This routine is a no-op except on its very first call for the process,
114 ** or for the first call after a call to sqlite3_shutdown.
115 **
116 ** The first thread to call this routine runs the initialization to
117 ** completion.  If subsequent threads call this routine before the first
118 ** thread has finished the initialization process, then the subsequent
119 ** threads must block until the first thread finishes with the initialization.
120 **
121 ** The first thread might call this routine recursively.  Recursive
122 ** calls to this routine should not block, of course.  Otherwise the
123 ** initialization process would never complete.
124 **
125 ** Let X be the first thread to enter this routine.  Let Y be some other
126 ** thread.  Then while the initial invocation of this routine by X is
127 ** incomplete, it is required that:
128 **
129 **    *  Calls to this routine from Y must block until the outer-most
130 **       call by X completes.
131 **
132 **    *  Recursive calls to this routine from thread X return immediately
133 **       without blocking.
134 */
135 int sqlite3_initialize(void){
136   MUTEX_LOGIC( sqlite3_mutex *pMaster; )       /* The main static mutex */
137   int rc;                                      /* Result code */
138 #ifdef SQLITE_EXTRA_INIT
139   int bRunExtraInit = 0;                       /* Extra initialization needed */
140 #endif
141 
142 #ifdef SQLITE_OMIT_WSD
143   rc = sqlite3_wsd_init(4096, 24);
144   if( rc!=SQLITE_OK ){
145     return rc;
146   }
147 #endif
148 
149   /* If the following assert() fails on some obscure processor/compiler
150   ** combination, the work-around is to set the correct pointer
151   ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
152   assert( SQLITE_PTRSIZE==sizeof(char*) );
153 
154   /* If SQLite is already completely initialized, then this call
155   ** to sqlite3_initialize() should be a no-op.  But the initialization
156   ** must be complete.  So isInit must not be set until the very end
157   ** of this routine.
158   */
159   if( sqlite3GlobalConfig.isInit ) return SQLITE_OK;
160 
161   /* Make sure the mutex subsystem is initialized.  If unable to
162   ** initialize the mutex subsystem, return early with the error.
163   ** If the system is so sick that we are unable to allocate a mutex,
164   ** there is not much SQLite is going to be able to do.
165   **
166   ** The mutex subsystem must take care of serializing its own
167   ** initialization.
168   */
169   rc = sqlite3MutexInit();
170   if( rc ) return rc;
171 
172   /* Initialize the malloc() system and the recursive pInitMutex mutex.
173   ** This operation is protected by the STATIC_MASTER mutex.  Note that
174   ** MutexAlloc() is called for a static mutex prior to initializing the
175   ** malloc subsystem - this implies that the allocation of a static
176   ** mutex must not require support from the malloc subsystem.
177   */
178   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
179   sqlite3_mutex_enter(pMaster);
180   sqlite3GlobalConfig.isMutexInit = 1;
181   if( !sqlite3GlobalConfig.isMallocInit ){
182     rc = sqlite3MallocInit();
183   }
184   if( rc==SQLITE_OK ){
185     sqlite3GlobalConfig.isMallocInit = 1;
186     if( !sqlite3GlobalConfig.pInitMutex ){
187       sqlite3GlobalConfig.pInitMutex =
188            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
189       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
190         rc = SQLITE_NOMEM_BKPT;
191       }
192     }
193   }
194   if( rc==SQLITE_OK ){
195     sqlite3GlobalConfig.nRefInitMutex++;
196   }
197   sqlite3_mutex_leave(pMaster);
198 
199   /* If rc is not SQLITE_OK at this point, then either the malloc
200   ** subsystem could not be initialized or the system failed to allocate
201   ** the pInitMutex mutex. Return an error in either case.  */
202   if( rc!=SQLITE_OK ){
203     return rc;
204   }
205 
206   /* Do the rest of the initialization under the recursive mutex so
207   ** that we will be able to handle recursive calls into
208   ** sqlite3_initialize().  The recursive calls normally come through
209   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
210   ** recursive calls might also be possible.
211   **
212   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
213   ** to the xInit method, so the xInit method need not be threadsafe.
214   **
215   ** The following mutex is what serializes access to the appdef pcache xInit
216   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
217   ** call to sqlite3PcacheInitialize().
218   */
219   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
220   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
221     sqlite3GlobalConfig.inProgress = 1;
222 #ifdef SQLITE_ENABLE_SQLLOG
223     {
224       extern void sqlite3_init_sqllog(void);
225       sqlite3_init_sqllog();
226     }
227 #endif
228     memset(&sqlite3BuiltinFunctions, 0, sizeof(sqlite3BuiltinFunctions));
229     sqlite3RegisterBuiltinFunctions();
230     if( sqlite3GlobalConfig.isPCacheInit==0 ){
231       rc = sqlite3PcacheInitialize();
232     }
233     if( rc==SQLITE_OK ){
234       sqlite3GlobalConfig.isPCacheInit = 1;
235       rc = sqlite3OsInit();
236     }
237     if( rc==SQLITE_OK ){
238       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
239           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
240       sqlite3GlobalConfig.isInit = 1;
241 #ifdef SQLITE_EXTRA_INIT
242       bRunExtraInit = 1;
243 #endif
244     }
245     sqlite3GlobalConfig.inProgress = 0;
246   }
247   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
248 
249   /* Go back under the static mutex and clean up the recursive
250   ** mutex to prevent a resource leak.
251   */
252   sqlite3_mutex_enter(pMaster);
253   sqlite3GlobalConfig.nRefInitMutex--;
254   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
255     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
256     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
257     sqlite3GlobalConfig.pInitMutex = 0;
258   }
259   sqlite3_mutex_leave(pMaster);
260 
261   /* The following is just a sanity check to make sure SQLite has
262   ** been compiled correctly.  It is important to run this code, but
263   ** we don't want to run it too often and soak up CPU cycles for no
264   ** reason.  So we run it once during initialization.
265   */
266 #ifndef NDEBUG
267 #ifndef SQLITE_OMIT_FLOATING_POINT
268   /* This section of code's only "output" is via assert() statements. */
269   if ( rc==SQLITE_OK ){
270     u64 x = (((u64)1)<<63)-1;
271     double y;
272     assert(sizeof(x)==8);
273     assert(sizeof(x)==sizeof(y));
274     memcpy(&y, &x, 8);
275     assert( sqlite3IsNaN(y) );
276   }
277 #endif
278 #endif
279 
280   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
281   ** compile-time option.
282   */
283 #ifdef SQLITE_EXTRA_INIT
284   if( bRunExtraInit ){
285     int SQLITE_EXTRA_INIT(const char*);
286     rc = SQLITE_EXTRA_INIT(0);
287   }
288 #endif
289 
290   return rc;
291 }
292 
293 /*
294 ** Undo the effects of sqlite3_initialize().  Must not be called while
295 ** there are outstanding database connections or memory allocations or
296 ** while any part of SQLite is otherwise in use in any thread.  This
297 ** routine is not threadsafe.  But it is safe to invoke this routine
298 ** on when SQLite is already shut down.  If SQLite is already shut down
299 ** when this routine is invoked, then this routine is a harmless no-op.
300 */
301 int sqlite3_shutdown(void){
302 #ifdef SQLITE_OMIT_WSD
303   int rc = sqlite3_wsd_init(4096, 24);
304   if( rc!=SQLITE_OK ){
305     return rc;
306   }
307 #endif
308 
309   if( sqlite3GlobalConfig.isInit ){
310 #ifdef SQLITE_EXTRA_SHUTDOWN
311     void SQLITE_EXTRA_SHUTDOWN(void);
312     SQLITE_EXTRA_SHUTDOWN();
313 #endif
314     sqlite3_os_end();
315     sqlite3_reset_auto_extension();
316     sqlite3GlobalConfig.isInit = 0;
317   }
318   if( sqlite3GlobalConfig.isPCacheInit ){
319     sqlite3PcacheShutdown();
320     sqlite3GlobalConfig.isPCacheInit = 0;
321   }
322   if( sqlite3GlobalConfig.isMallocInit ){
323     sqlite3MallocEnd();
324     sqlite3GlobalConfig.isMallocInit = 0;
325 
326 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
327     /* The heap subsystem has now been shutdown and these values are supposed
328     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
329     ** which would rely on that heap subsystem; therefore, make sure these
330     ** values cannot refer to heap memory that was just invalidated when the
331     ** heap subsystem was shutdown.  This is only done if the current call to
332     ** this function resulted in the heap subsystem actually being shutdown.
333     */
334     sqlite3_data_directory = 0;
335     sqlite3_temp_directory = 0;
336 #endif
337   }
338   if( sqlite3GlobalConfig.isMutexInit ){
339     sqlite3MutexEnd();
340     sqlite3GlobalConfig.isMutexInit = 0;
341   }
342 
343   return SQLITE_OK;
344 }
345 
346 /*
347 ** This API allows applications to modify the global configuration of
348 ** the SQLite library at run-time.
349 **
350 ** This routine should only be called when there are no outstanding
351 ** database connections or memory allocations.  This routine is not
352 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
353 ** behavior.
354 */
355 int sqlite3_config(int op, ...){
356   va_list ap;
357   int rc = SQLITE_OK;
358 
359   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
360   ** the SQLite library is in use. */
361   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
362 
363   va_start(ap, op);
364   switch( op ){
365 
366     /* Mutex configuration options are only available in a threadsafe
367     ** compile.
368     */
369 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
370     case SQLITE_CONFIG_SINGLETHREAD: {
371       /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
372       ** Single-thread. */
373       sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
374       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
375       break;
376     }
377 #endif
378 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
379     case SQLITE_CONFIG_MULTITHREAD: {
380       /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
381       ** Multi-thread. */
382       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
383       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
384       break;
385     }
386 #endif
387 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
388     case SQLITE_CONFIG_SERIALIZED: {
389       /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
390       ** Serialized. */
391       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
392       sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
393       break;
394     }
395 #endif
396 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
397     case SQLITE_CONFIG_MUTEX: {
398       /* Specify an alternative mutex implementation */
399       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
400       break;
401     }
402 #endif
403 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
404     case SQLITE_CONFIG_GETMUTEX: {
405       /* Retrieve the current mutex implementation */
406       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
407       break;
408     }
409 #endif
410 
411     case SQLITE_CONFIG_MALLOC: {
412       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
413       ** single argument which is a pointer to an instance of the
414       ** sqlite3_mem_methods structure. The argument specifies alternative
415       ** low-level memory allocation routines to be used in place of the memory
416       ** allocation routines built into SQLite. */
417       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
418       break;
419     }
420     case SQLITE_CONFIG_GETMALLOC: {
421       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
422       ** single argument which is a pointer to an instance of the
423       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
424       ** filled with the currently defined memory allocation routines. */
425       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
426       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
427       break;
428     }
429     case SQLITE_CONFIG_MEMSTATUS: {
430       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
431       ** single argument of type int, interpreted as a boolean, which enables
432       ** or disables the collection of memory allocation statistics. */
433       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
434       break;
435     }
436     case SQLITE_CONFIG_SCRATCH: {
437       /* EVIDENCE-OF: R-08404-60887 There are three arguments to
438       ** SQLITE_CONFIG_SCRATCH: A pointer an 8-byte aligned memory buffer from
439       ** which the scratch allocations will be drawn, the size of each scratch
440       ** allocation (sz), and the maximum number of scratch allocations (N). */
441       sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
442       sqlite3GlobalConfig.szScratch = va_arg(ap, int);
443       sqlite3GlobalConfig.nScratch = va_arg(ap, int);
444       break;
445     }
446     case SQLITE_CONFIG_PAGECACHE: {
447       /* EVIDENCE-OF: R-18761-36601 There are three arguments to
448       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory (pMem),
449       ** the size of each page cache line (sz), and the number of cache lines
450       ** (N). */
451       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
452       sqlite3GlobalConfig.szPage = va_arg(ap, int);
453       sqlite3GlobalConfig.nPage = va_arg(ap, int);
454       break;
455     }
456     case SQLITE_CONFIG_PCACHE_HDRSZ: {
457       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
458       ** a single parameter which is a pointer to an integer and writes into
459       ** that integer the number of extra bytes per page required for each page
460       ** in SQLITE_CONFIG_PAGECACHE. */
461       *va_arg(ap, int*) =
462           sqlite3HeaderSizeBtree() +
463           sqlite3HeaderSizePcache() +
464           sqlite3HeaderSizePcache1();
465       break;
466     }
467 
468     case SQLITE_CONFIG_PCACHE: {
469       /* no-op */
470       break;
471     }
472     case SQLITE_CONFIG_GETPCACHE: {
473       /* now an error */
474       rc = SQLITE_ERROR;
475       break;
476     }
477 
478     case SQLITE_CONFIG_PCACHE2: {
479       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
480       ** single argument which is a pointer to an sqlite3_pcache_methods2
481       ** object. This object specifies the interface to a custom page cache
482       ** implementation. */
483       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
484       break;
485     }
486     case SQLITE_CONFIG_GETPCACHE2: {
487       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
488       ** single argument which is a pointer to an sqlite3_pcache_methods2
489       ** object. SQLite copies of the current page cache implementation into
490       ** that object. */
491       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
492         sqlite3PCacheSetDefault();
493       }
494       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
495       break;
496     }
497 
498 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
499 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
500 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
501 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
502     case SQLITE_CONFIG_HEAP: {
503       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
504       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
505       ** number of bytes in the memory buffer, and the minimum allocation size.
506       */
507       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
508       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
509       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
510 
511       if( sqlite3GlobalConfig.mnReq<1 ){
512         sqlite3GlobalConfig.mnReq = 1;
513       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
514         /* cap min request size at 2^12 */
515         sqlite3GlobalConfig.mnReq = (1<<12);
516       }
517 
518       if( sqlite3GlobalConfig.pHeap==0 ){
519         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
520         ** is NULL, then SQLite reverts to using its default memory allocator
521         ** (the system malloc() implementation), undoing any prior invocation of
522         ** SQLITE_CONFIG_MALLOC.
523         **
524         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
525         ** revert to its default implementation when sqlite3_initialize() is run
526         */
527         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
528       }else{
529         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
530         ** alternative memory allocator is engaged to handle all of SQLites
531         ** memory allocation needs. */
532 #ifdef SQLITE_ENABLE_MEMSYS3
533         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
534 #endif
535 #ifdef SQLITE_ENABLE_MEMSYS5
536         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
537 #endif
538       }
539       break;
540     }
541 #endif
542 
543     case SQLITE_CONFIG_LOOKASIDE: {
544       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
545       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
546       break;
547     }
548 
549     /* Record a pointer to the logger function and its first argument.
550     ** The default is NULL.  Logging is disabled if the function pointer is
551     ** NULL.
552     */
553     case SQLITE_CONFIG_LOG: {
554       /* MSVC is picky about pulling func ptrs from va lists.
555       ** http://support.microsoft.com/kb/47961
556       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
557       */
558       typedef void(*LOGFUNC_t)(void*,int,const char*);
559       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
560       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
561       break;
562     }
563 
564     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
565     ** can be changed at start-time using the
566     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
567     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
568     */
569     case SQLITE_CONFIG_URI: {
570       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
571       ** argument of type int. If non-zero, then URI handling is globally
572       ** enabled. If the parameter is zero, then URI handling is globally
573       ** disabled. */
574       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
575       break;
576     }
577 
578     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
579       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
580       ** option takes a single integer argument which is interpreted as a
581       ** boolean in order to enable or disable the use of covering indices for
582       ** full table scans in the query optimizer. */
583       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
584       break;
585     }
586 
587 #ifdef SQLITE_ENABLE_SQLLOG
588     case SQLITE_CONFIG_SQLLOG: {
589       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
590       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
591       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
592       break;
593     }
594 #endif
595 
596     case SQLITE_CONFIG_MMAP_SIZE: {
597       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
598       ** integer (sqlite3_int64) values that are the default mmap size limit
599       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
600       ** mmap size limit. */
601       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
602       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
603       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
604       ** negative, then that argument is changed to its compile-time default.
605       **
606       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
607       ** silently truncated if necessary so that it does not exceed the
608       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
609       ** compile-time option.
610       */
611       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
612         mxMmap = SQLITE_MAX_MMAP_SIZE;
613       }
614       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
615       if( szMmap>mxMmap) szMmap = mxMmap;
616       sqlite3GlobalConfig.mxMmap = mxMmap;
617       sqlite3GlobalConfig.szMmap = szMmap;
618       break;
619     }
620 
621 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
622     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
623       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
624       ** unsigned integer value that specifies the maximum size of the created
625       ** heap. */
626       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
627       break;
628     }
629 #endif
630 
631     case SQLITE_CONFIG_PMASZ: {
632       sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
633       break;
634     }
635 
636     default: {
637       rc = SQLITE_ERROR;
638       break;
639     }
640   }
641   va_end(ap);
642   return rc;
643 }
644 
645 /*
646 ** Set up the lookaside buffers for a database connection.
647 ** Return SQLITE_OK on success.
648 ** If lookaside is already active, return SQLITE_BUSY.
649 **
650 ** The sz parameter is the number of bytes in each lookaside slot.
651 ** The cnt parameter is the number of slots.  If pStart is NULL the
652 ** space for the lookaside memory is obtained from sqlite3_malloc().
653 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
654 ** the lookaside memory.
655 */
656 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
657 #ifndef SQLITE_OMIT_LOOKASIDE
658   void *pStart;
659   if( db->lookaside.nOut ){
660     return SQLITE_BUSY;
661   }
662   /* Free any existing lookaside buffer for this handle before
663   ** allocating a new one so we don't have to have space for
664   ** both at the same time.
665   */
666   if( db->lookaside.bMalloced ){
667     sqlite3_free(db->lookaside.pStart);
668   }
669   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
670   ** than a pointer to be useful.
671   */
672   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
673   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
674   if( cnt<0 ) cnt = 0;
675   if( sz==0 || cnt==0 ){
676     sz = 0;
677     pStart = 0;
678   }else if( pBuf==0 ){
679     sqlite3BeginBenignMalloc();
680     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
681     sqlite3EndBenignMalloc();
682     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
683   }else{
684     pStart = pBuf;
685   }
686   db->lookaside.pStart = pStart;
687   db->lookaside.pFree = 0;
688   db->lookaside.sz = (u16)sz;
689   if( pStart ){
690     int i;
691     LookasideSlot *p;
692     assert( sz > (int)sizeof(LookasideSlot*) );
693     p = (LookasideSlot*)pStart;
694     for(i=cnt-1; i>=0; i--){
695       p->pNext = db->lookaside.pFree;
696       db->lookaside.pFree = p;
697       p = (LookasideSlot*)&((u8*)p)[sz];
698     }
699     db->lookaside.pEnd = p;
700     db->lookaside.bDisable = 0;
701     db->lookaside.bMalloced = pBuf==0 ?1:0;
702   }else{
703     db->lookaside.pStart = db;
704     db->lookaside.pEnd = db;
705     db->lookaside.bDisable = 1;
706     db->lookaside.bMalloced = 0;
707   }
708 #endif /* SQLITE_OMIT_LOOKASIDE */
709   return SQLITE_OK;
710 }
711 
712 /*
713 ** Return the mutex associated with a database connection.
714 */
715 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
716 #ifdef SQLITE_ENABLE_API_ARMOR
717   if( !sqlite3SafetyCheckOk(db) ){
718     (void)SQLITE_MISUSE_BKPT;
719     return 0;
720   }
721 #endif
722   return db->mutex;
723 }
724 
725 /*
726 ** Free up as much memory as we can from the given database
727 ** connection.
728 */
729 int sqlite3_db_release_memory(sqlite3 *db){
730   int i;
731 
732 #ifdef SQLITE_ENABLE_API_ARMOR
733   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
734 #endif
735   sqlite3_mutex_enter(db->mutex);
736   sqlite3BtreeEnterAll(db);
737   for(i=0; i<db->nDb; i++){
738     Btree *pBt = db->aDb[i].pBt;
739     if( pBt ){
740       Pager *pPager = sqlite3BtreePager(pBt);
741       sqlite3PagerShrink(pPager);
742     }
743   }
744   sqlite3BtreeLeaveAll(db);
745   sqlite3_mutex_leave(db->mutex);
746   return SQLITE_OK;
747 }
748 
749 /*
750 ** Flush any dirty pages in the pager-cache for any attached database
751 ** to disk.
752 */
753 int sqlite3_db_cacheflush(sqlite3 *db){
754   int i;
755   int rc = SQLITE_OK;
756   int bSeenBusy = 0;
757 
758 #ifdef SQLITE_ENABLE_API_ARMOR
759   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
760 #endif
761   sqlite3_mutex_enter(db->mutex);
762   sqlite3BtreeEnterAll(db);
763   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
764     Btree *pBt = db->aDb[i].pBt;
765     if( pBt && sqlite3BtreeIsInTrans(pBt) ){
766       Pager *pPager = sqlite3BtreePager(pBt);
767       rc = sqlite3PagerFlush(pPager);
768       if( rc==SQLITE_BUSY ){
769         bSeenBusy = 1;
770         rc = SQLITE_OK;
771       }
772     }
773   }
774   sqlite3BtreeLeaveAll(db);
775   sqlite3_mutex_leave(db->mutex);
776   return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
777 }
778 
779 /*
780 ** Configuration settings for an individual database connection
781 */
782 int sqlite3_db_config(sqlite3 *db, int op, ...){
783   va_list ap;
784   int rc;
785   va_start(ap, op);
786   switch( op ){
787     case SQLITE_DBCONFIG_LOOKASIDE: {
788       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
789       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
790       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
791       rc = setupLookaside(db, pBuf, sz, cnt);
792       break;
793     }
794     default: {
795       static const struct {
796         int op;      /* The opcode */
797         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
798       } aFlagOp[] = {
799         { SQLITE_DBCONFIG_ENABLE_FKEY,    SQLITE_ForeignKeys    },
800         { SQLITE_DBCONFIG_ENABLE_TRIGGER, SQLITE_EnableTrigger  },
801       };
802       unsigned int i;
803       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
804       for(i=0; i<ArraySize(aFlagOp); i++){
805         if( aFlagOp[i].op==op ){
806           int onoff = va_arg(ap, int);
807           int *pRes = va_arg(ap, int*);
808           int oldFlags = db->flags;
809           if( onoff>0 ){
810             db->flags |= aFlagOp[i].mask;
811           }else if( onoff==0 ){
812             db->flags &= ~aFlagOp[i].mask;
813           }
814           if( oldFlags!=db->flags ){
815             sqlite3ExpirePreparedStatements(db);
816           }
817           if( pRes ){
818             *pRes = (db->flags & aFlagOp[i].mask)!=0;
819           }
820           rc = SQLITE_OK;
821           break;
822         }
823       }
824       break;
825     }
826   }
827   va_end(ap);
828   return rc;
829 }
830 
831 
832 /*
833 ** Return true if the buffer z[0..n-1] contains all spaces.
834 */
835 static int allSpaces(const char *z, int n){
836   while( n>0 && z[n-1]==' ' ){ n--; }
837   return n==0;
838 }
839 
840 /*
841 ** This is the default collating function named "BINARY" which is always
842 ** available.
843 **
844 ** If the padFlag argument is not NULL then space padding at the end
845 ** of strings is ignored.  This implements the RTRIM collation.
846 */
847 static int binCollFunc(
848   void *padFlag,
849   int nKey1, const void *pKey1,
850   int nKey2, const void *pKey2
851 ){
852   int rc, n;
853   n = nKey1<nKey2 ? nKey1 : nKey2;
854   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
855   ** strings byte by byte using the memcmp() function from the standard C
856   ** library. */
857   rc = memcmp(pKey1, pKey2, n);
858   if( rc==0 ){
859     if( padFlag
860      && allSpaces(((char*)pKey1)+n, nKey1-n)
861      && allSpaces(((char*)pKey2)+n, nKey2-n)
862     ){
863       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
864       ** spaces at the end of either string do not change the result. In other
865       ** words, strings will compare equal to one another as long as they
866       ** differ only in the number of spaces at the end.
867       */
868     }else{
869       rc = nKey1 - nKey2;
870     }
871   }
872   return rc;
873 }
874 
875 /*
876 ** Another built-in collating sequence: NOCASE.
877 **
878 ** This collating sequence is intended to be used for "case independent
879 ** comparison". SQLite's knowledge of upper and lower case equivalents
880 ** extends only to the 26 characters used in the English language.
881 **
882 ** At the moment there is only a UTF-8 implementation.
883 */
884 static int nocaseCollatingFunc(
885   void *NotUsed,
886   int nKey1, const void *pKey1,
887   int nKey2, const void *pKey2
888 ){
889   int r = sqlite3StrNICmp(
890       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
891   UNUSED_PARAMETER(NotUsed);
892   if( 0==r ){
893     r = nKey1-nKey2;
894   }
895   return r;
896 }
897 
898 /*
899 ** Return the ROWID of the most recent insert
900 */
901 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
902 #ifdef SQLITE_ENABLE_API_ARMOR
903   if( !sqlite3SafetyCheckOk(db) ){
904     (void)SQLITE_MISUSE_BKPT;
905     return 0;
906   }
907 #endif
908   return db->lastRowid;
909 }
910 
911 /*
912 ** Return the number of changes in the most recent call to sqlite3_exec().
913 */
914 int sqlite3_changes(sqlite3 *db){
915 #ifdef SQLITE_ENABLE_API_ARMOR
916   if( !sqlite3SafetyCheckOk(db) ){
917     (void)SQLITE_MISUSE_BKPT;
918     return 0;
919   }
920 #endif
921   return db->nChange;
922 }
923 
924 /*
925 ** Return the number of changes since the database handle was opened.
926 */
927 int sqlite3_total_changes(sqlite3 *db){
928 #ifdef SQLITE_ENABLE_API_ARMOR
929   if( !sqlite3SafetyCheckOk(db) ){
930     (void)SQLITE_MISUSE_BKPT;
931     return 0;
932   }
933 #endif
934   return db->nTotalChange;
935 }
936 
937 /*
938 ** Close all open savepoints. This function only manipulates fields of the
939 ** database handle object, it does not close any savepoints that may be open
940 ** at the b-tree/pager level.
941 */
942 void sqlite3CloseSavepoints(sqlite3 *db){
943   while( db->pSavepoint ){
944     Savepoint *pTmp = db->pSavepoint;
945     db->pSavepoint = pTmp->pNext;
946     sqlite3DbFree(db, pTmp);
947   }
948   db->nSavepoint = 0;
949   db->nStatement = 0;
950   db->isTransactionSavepoint = 0;
951 }
952 
953 /*
954 ** Invoke the destructor function associated with FuncDef p, if any. Except,
955 ** if this is not the last copy of the function, do not invoke it. Multiple
956 ** copies of a single function are created when create_function() is called
957 ** with SQLITE_ANY as the encoding.
958 */
959 static void functionDestroy(sqlite3 *db, FuncDef *p){
960   FuncDestructor *pDestructor = p->u.pDestructor;
961   if( pDestructor ){
962     pDestructor->nRef--;
963     if( pDestructor->nRef==0 ){
964       pDestructor->xDestroy(pDestructor->pUserData);
965       sqlite3DbFree(db, pDestructor);
966     }
967   }
968 }
969 
970 /*
971 ** Disconnect all sqlite3_vtab objects that belong to database connection
972 ** db. This is called when db is being closed.
973 */
974 static void disconnectAllVtab(sqlite3 *db){
975 #ifndef SQLITE_OMIT_VIRTUALTABLE
976   int i;
977   HashElem *p;
978   sqlite3BtreeEnterAll(db);
979   for(i=0; i<db->nDb; i++){
980     Schema *pSchema = db->aDb[i].pSchema;
981     if( db->aDb[i].pSchema ){
982       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
983         Table *pTab = (Table *)sqliteHashData(p);
984         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
985       }
986     }
987   }
988   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
989     Module *pMod = (Module *)sqliteHashData(p);
990     if( pMod->pEpoTab ){
991       sqlite3VtabDisconnect(db, pMod->pEpoTab);
992     }
993   }
994   sqlite3VtabUnlockList(db);
995   sqlite3BtreeLeaveAll(db);
996 #else
997   UNUSED_PARAMETER(db);
998 #endif
999 }
1000 
1001 /*
1002 ** Return TRUE if database connection db has unfinalized prepared
1003 ** statements or unfinished sqlite3_backup objects.
1004 */
1005 static int connectionIsBusy(sqlite3 *db){
1006   int j;
1007   assert( sqlite3_mutex_held(db->mutex) );
1008   if( db->pVdbe ) return 1;
1009   for(j=0; j<db->nDb; j++){
1010     Btree *pBt = db->aDb[j].pBt;
1011     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1012   }
1013   return 0;
1014 }
1015 
1016 /*
1017 ** Close an existing SQLite database
1018 */
1019 static int sqlite3Close(sqlite3 *db, int forceZombie){
1020   if( !db ){
1021     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1022     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1023     return SQLITE_OK;
1024   }
1025   if( !sqlite3SafetyCheckSickOrOk(db) ){
1026     return SQLITE_MISUSE_BKPT;
1027   }
1028   sqlite3_mutex_enter(db->mutex);
1029 
1030   /* Force xDisconnect calls on all virtual tables */
1031   disconnectAllVtab(db);
1032 
1033   /* If a transaction is open, the disconnectAllVtab() call above
1034   ** will not have called the xDisconnect() method on any virtual
1035   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1036   ** call will do so. We need to do this before the check for active
1037   ** SQL statements below, as the v-table implementation may be storing
1038   ** some prepared statements internally.
1039   */
1040   sqlite3VtabRollback(db);
1041 
1042   /* Legacy behavior (sqlite3_close() behavior) is to return
1043   ** SQLITE_BUSY if the connection can not be closed immediately.
1044   */
1045   if( !forceZombie && connectionIsBusy(db) ){
1046     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1047        "statements or unfinished backups");
1048     sqlite3_mutex_leave(db->mutex);
1049     return SQLITE_BUSY;
1050   }
1051 
1052 #ifdef SQLITE_ENABLE_SQLLOG
1053   if( sqlite3GlobalConfig.xSqllog ){
1054     /* Closing the handle. Fourth parameter is passed the value 2. */
1055     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1056   }
1057 #endif
1058 
1059   /* Convert the connection into a zombie and then close it.
1060   */
1061   db->magic = SQLITE_MAGIC_ZOMBIE;
1062   sqlite3LeaveMutexAndCloseZombie(db);
1063   return SQLITE_OK;
1064 }
1065 
1066 /*
1067 ** Two variations on the public interface for closing a database
1068 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1069 ** leaves the connection option if there are unfinalized prepared
1070 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1071 ** version forces the connection to become a zombie if there are
1072 ** unclosed resources, and arranges for deallocation when the last
1073 ** prepare statement or sqlite3_backup closes.
1074 */
1075 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1076 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1077 
1078 
1079 /*
1080 ** Close the mutex on database connection db.
1081 **
1082 ** Furthermore, if database connection db is a zombie (meaning that there
1083 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1084 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1085 ** finished, then free all resources.
1086 */
1087 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1088   HashElem *i;                    /* Hash table iterator */
1089   int j;
1090 
1091   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1092   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1093   ** then just leave the mutex and return.
1094   */
1095   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1096     sqlite3_mutex_leave(db->mutex);
1097     return;
1098   }
1099 
1100   /* If we reach this point, it means that the database connection has
1101   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1102   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1103   ** go ahead and free all resources.
1104   */
1105 
1106   /* If a transaction is open, roll it back. This also ensures that if
1107   ** any database schemas have been modified by an uncommitted transaction
1108   ** they are reset. And that the required b-tree mutex is held to make
1109   ** the pager rollback and schema reset an atomic operation. */
1110   sqlite3RollbackAll(db, SQLITE_OK);
1111 
1112   /* Free any outstanding Savepoint structures. */
1113   sqlite3CloseSavepoints(db);
1114 
1115   /* Close all database connections */
1116   for(j=0; j<db->nDb; j++){
1117     struct Db *pDb = &db->aDb[j];
1118     if( pDb->pBt ){
1119       sqlite3BtreeClose(pDb->pBt);
1120       pDb->pBt = 0;
1121       if( j!=1 ){
1122         pDb->pSchema = 0;
1123       }
1124     }
1125   }
1126   /* Clear the TEMP schema separately and last */
1127   if( db->aDb[1].pSchema ){
1128     sqlite3SchemaClear(db->aDb[1].pSchema);
1129   }
1130   sqlite3VtabUnlockList(db);
1131 
1132   /* Free up the array of auxiliary databases */
1133   sqlite3CollapseDatabaseArray(db);
1134   assert( db->nDb<=2 );
1135   assert( db->aDb==db->aDbStatic );
1136 
1137   /* Tell the code in notify.c that the connection no longer holds any
1138   ** locks and does not require any further unlock-notify callbacks.
1139   */
1140   sqlite3ConnectionClosed(db);
1141 
1142   for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
1143     FuncDef *pNext, *p;
1144     p = sqliteHashData(i);
1145     do{
1146       functionDestroy(db, p);
1147       pNext = p->pNext;
1148       sqlite3DbFree(db, p);
1149       p = pNext;
1150     }while( p );
1151   }
1152   sqlite3HashClear(&db->aFunc);
1153   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1154     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1155     /* Invoke any destructors registered for collation sequence user data. */
1156     for(j=0; j<3; j++){
1157       if( pColl[j].xDel ){
1158         pColl[j].xDel(pColl[j].pUser);
1159       }
1160     }
1161     sqlite3DbFree(db, pColl);
1162   }
1163   sqlite3HashClear(&db->aCollSeq);
1164 #ifndef SQLITE_OMIT_VIRTUALTABLE
1165   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1166     Module *pMod = (Module *)sqliteHashData(i);
1167     if( pMod->xDestroy ){
1168       pMod->xDestroy(pMod->pAux);
1169     }
1170     sqlite3VtabEponymousTableClear(db, pMod);
1171     sqlite3DbFree(db, pMod);
1172   }
1173   sqlite3HashClear(&db->aModule);
1174 #endif
1175 
1176   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1177   sqlite3ValueFree(db->pErr);
1178   sqlite3CloseExtensions(db);
1179 #if SQLITE_USER_AUTHENTICATION
1180   sqlite3_free(db->auth.zAuthUser);
1181   sqlite3_free(db->auth.zAuthPW);
1182 #endif
1183 
1184   db->magic = SQLITE_MAGIC_ERROR;
1185 
1186   /* The temp-database schema is allocated differently from the other schema
1187   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1188   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1189   ** the same sqliteMalloc() as the one that allocates the database
1190   ** structure?
1191   */
1192   sqlite3DbFree(db, db->aDb[1].pSchema);
1193   sqlite3_mutex_leave(db->mutex);
1194   db->magic = SQLITE_MAGIC_CLOSED;
1195   sqlite3_mutex_free(db->mutex);
1196   assert( db->lookaside.nOut==0 );  /* Fails on a lookaside memory leak */
1197   if( db->lookaside.bMalloced ){
1198     sqlite3_free(db->lookaside.pStart);
1199   }
1200   sqlite3_free(db);
1201 }
1202 
1203 /*
1204 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1205 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1206 ** breaker") and made to return tripCode if there are any further
1207 ** attempts to use that cursor.  Read cursors remain open and valid
1208 ** but are "saved" in case the table pages are moved around.
1209 */
1210 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1211   int i;
1212   int inTrans = 0;
1213   int schemaChange;
1214   assert( sqlite3_mutex_held(db->mutex) );
1215   sqlite3BeginBenignMalloc();
1216 
1217   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1218   ** This is important in case the transaction being rolled back has
1219   ** modified the database schema. If the b-tree mutexes are not taken
1220   ** here, then another shared-cache connection might sneak in between
1221   ** the database rollback and schema reset, which can cause false
1222   ** corruption reports in some cases.  */
1223   sqlite3BtreeEnterAll(db);
1224   schemaChange = (db->flags & SQLITE_InternChanges)!=0 && db->init.busy==0;
1225 
1226   for(i=0; i<db->nDb; i++){
1227     Btree *p = db->aDb[i].pBt;
1228     if( p ){
1229       if( sqlite3BtreeIsInTrans(p) ){
1230         inTrans = 1;
1231       }
1232       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1233     }
1234   }
1235   sqlite3VtabRollback(db);
1236   sqlite3EndBenignMalloc();
1237 
1238   if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
1239     sqlite3ExpirePreparedStatements(db);
1240     sqlite3ResetAllSchemasOfConnection(db);
1241   }
1242   sqlite3BtreeLeaveAll(db);
1243 
1244   /* Any deferred constraint violations have now been resolved. */
1245   db->nDeferredCons = 0;
1246   db->nDeferredImmCons = 0;
1247   db->flags &= ~SQLITE_DeferFKs;
1248 
1249   /* If one has been configured, invoke the rollback-hook callback */
1250   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1251     db->xRollbackCallback(db->pRollbackArg);
1252   }
1253 }
1254 
1255 /*
1256 ** Return a static string containing the name corresponding to the error code
1257 ** specified in the argument.
1258 */
1259 #if defined(SQLITE_NEED_ERR_NAME)
1260 const char *sqlite3ErrName(int rc){
1261   const char *zName = 0;
1262   int i, origRc = rc;
1263   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1264     switch( rc ){
1265       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1266       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1267       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1268       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1269       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1270       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1271       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1272       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1273       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1274       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1275       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1276       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1277       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1278       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1279       case SQLITE_READONLY_CANTLOCK:  zName = "SQLITE_READONLY_CANTLOCK"; break;
1280       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1281       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1282       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1283       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1284       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1285       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1286       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1287       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1288       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1289       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1290       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1291       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1292       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1293       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1294       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1295       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1296       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1297                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1298       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1299       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1300       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1301       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1302       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1303       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1304       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1305       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1306       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1307       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1308       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1309       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1310       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1311       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1312       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1313       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1314       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1315       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1316       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1317       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1318       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1319       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1320       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1321       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1322       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1323       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1324       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1325       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1326       case SQLITE_CONSTRAINT_FOREIGNKEY:
1327                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1328       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1329       case SQLITE_CONSTRAINT_PRIMARYKEY:
1330                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1331       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1332       case SQLITE_CONSTRAINT_COMMITHOOK:
1333                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1334       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1335       case SQLITE_CONSTRAINT_FUNCTION:
1336                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1337       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1338       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1339       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1340       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1341       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1342       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1343       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1344       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1345       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1346       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1347       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1348       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1349                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1350       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1351       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1352       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1353     }
1354   }
1355   if( zName==0 ){
1356     static char zBuf[50];
1357     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1358     zName = zBuf;
1359   }
1360   return zName;
1361 }
1362 #endif
1363 
1364 /*
1365 ** Return a static string that describes the kind of error specified in the
1366 ** argument.
1367 */
1368 const char *sqlite3ErrStr(int rc){
1369   static const char* const aMsg[] = {
1370     /* SQLITE_OK          */ "not an error",
1371     /* SQLITE_ERROR       */ "SQL logic error or missing database",
1372     /* SQLITE_INTERNAL    */ 0,
1373     /* SQLITE_PERM        */ "access permission denied",
1374     /* SQLITE_ABORT       */ "callback requested query abort",
1375     /* SQLITE_BUSY        */ "database is locked",
1376     /* SQLITE_LOCKED      */ "database table is locked",
1377     /* SQLITE_NOMEM       */ "out of memory",
1378     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1379     /* SQLITE_INTERRUPT   */ "interrupted",
1380     /* SQLITE_IOERR       */ "disk I/O error",
1381     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1382     /* SQLITE_NOTFOUND    */ "unknown operation",
1383     /* SQLITE_FULL        */ "database or disk is full",
1384     /* SQLITE_CANTOPEN    */ "unable to open database file",
1385     /* SQLITE_PROTOCOL    */ "locking protocol",
1386     /* SQLITE_EMPTY       */ "table contains no data",
1387     /* SQLITE_SCHEMA      */ "database schema has changed",
1388     /* SQLITE_TOOBIG      */ "string or blob too big",
1389     /* SQLITE_CONSTRAINT  */ "constraint failed",
1390     /* SQLITE_MISMATCH    */ "datatype mismatch",
1391     /* SQLITE_MISUSE      */ "library routine called out of sequence",
1392     /* SQLITE_NOLFS       */ "large file support is disabled",
1393     /* SQLITE_AUTH        */ "authorization denied",
1394     /* SQLITE_FORMAT      */ "auxiliary database format error",
1395     /* SQLITE_RANGE       */ "bind or column index out of range",
1396     /* SQLITE_NOTADB      */ "file is encrypted or is not a database",
1397   };
1398   const char *zErr = "unknown error";
1399   switch( rc ){
1400     case SQLITE_ABORT_ROLLBACK: {
1401       zErr = "abort due to ROLLBACK";
1402       break;
1403     }
1404     default: {
1405       rc &= 0xff;
1406       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1407         zErr = aMsg[rc];
1408       }
1409       break;
1410     }
1411   }
1412   return zErr;
1413 }
1414 
1415 /*
1416 ** This routine implements a busy callback that sleeps and tries
1417 ** again until a timeout value is reached.  The timeout value is
1418 ** an integer number of milliseconds passed in as the first
1419 ** argument.
1420 */
1421 static int sqliteDefaultBusyCallback(
1422  void *ptr,               /* Database connection */
1423  int count                /* Number of times table has been busy */
1424 ){
1425 #if SQLITE_OS_WIN || HAVE_USLEEP
1426   static const u8 delays[] =
1427      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1428   static const u8 totals[] =
1429      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1430 # define NDELAY ArraySize(delays)
1431   sqlite3 *db = (sqlite3 *)ptr;
1432   int timeout = db->busyTimeout;
1433   int delay, prior;
1434 
1435   assert( count>=0 );
1436   if( count < NDELAY ){
1437     delay = delays[count];
1438     prior = totals[count];
1439   }else{
1440     delay = delays[NDELAY-1];
1441     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1442   }
1443   if( prior + delay > timeout ){
1444     delay = timeout - prior;
1445     if( delay<=0 ) return 0;
1446   }
1447   sqlite3OsSleep(db->pVfs, delay*1000);
1448   return 1;
1449 #else
1450   sqlite3 *db = (sqlite3 *)ptr;
1451   int timeout = ((sqlite3 *)ptr)->busyTimeout;
1452   if( (count+1)*1000 > timeout ){
1453     return 0;
1454   }
1455   sqlite3OsSleep(db->pVfs, 1000000);
1456   return 1;
1457 #endif
1458 }
1459 
1460 /*
1461 ** Invoke the given busy handler.
1462 **
1463 ** This routine is called when an operation failed with a lock.
1464 ** If this routine returns non-zero, the lock is retried.  If it
1465 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1466 */
1467 int sqlite3InvokeBusyHandler(BusyHandler *p){
1468   int rc;
1469   if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;
1470   rc = p->xFunc(p->pArg, p->nBusy);
1471   if( rc==0 ){
1472     p->nBusy = -1;
1473   }else{
1474     p->nBusy++;
1475   }
1476   return rc;
1477 }
1478 
1479 /*
1480 ** This routine sets the busy callback for an Sqlite database to the
1481 ** given callback function with the given argument.
1482 */
1483 int sqlite3_busy_handler(
1484   sqlite3 *db,
1485   int (*xBusy)(void*,int),
1486   void *pArg
1487 ){
1488 #ifdef SQLITE_ENABLE_API_ARMOR
1489   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1490 #endif
1491   sqlite3_mutex_enter(db->mutex);
1492   db->busyHandler.xFunc = xBusy;
1493   db->busyHandler.pArg = pArg;
1494   db->busyHandler.nBusy = 0;
1495   db->busyTimeout = 0;
1496   sqlite3_mutex_leave(db->mutex);
1497   return SQLITE_OK;
1498 }
1499 
1500 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1501 /*
1502 ** This routine sets the progress callback for an Sqlite database to the
1503 ** given callback function with the given argument. The progress callback will
1504 ** be invoked every nOps opcodes.
1505 */
1506 void sqlite3_progress_handler(
1507   sqlite3 *db,
1508   int nOps,
1509   int (*xProgress)(void*),
1510   void *pArg
1511 ){
1512 #ifdef SQLITE_ENABLE_API_ARMOR
1513   if( !sqlite3SafetyCheckOk(db) ){
1514     (void)SQLITE_MISUSE_BKPT;
1515     return;
1516   }
1517 #endif
1518   sqlite3_mutex_enter(db->mutex);
1519   if( nOps>0 ){
1520     db->xProgress = xProgress;
1521     db->nProgressOps = (unsigned)nOps;
1522     db->pProgressArg = pArg;
1523   }else{
1524     db->xProgress = 0;
1525     db->nProgressOps = 0;
1526     db->pProgressArg = 0;
1527   }
1528   sqlite3_mutex_leave(db->mutex);
1529 }
1530 #endif
1531 
1532 
1533 /*
1534 ** This routine installs a default busy handler that waits for the
1535 ** specified number of milliseconds before returning 0.
1536 */
1537 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1538 #ifdef SQLITE_ENABLE_API_ARMOR
1539   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1540 #endif
1541   if( ms>0 ){
1542     sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
1543     db->busyTimeout = ms;
1544   }else{
1545     sqlite3_busy_handler(db, 0, 0);
1546   }
1547   return SQLITE_OK;
1548 }
1549 
1550 /*
1551 ** Cause any pending operation to stop at its earliest opportunity.
1552 */
1553 void sqlite3_interrupt(sqlite3 *db){
1554 #ifdef SQLITE_ENABLE_API_ARMOR
1555   if( !sqlite3SafetyCheckOk(db) ){
1556     (void)SQLITE_MISUSE_BKPT;
1557     return;
1558   }
1559 #endif
1560   db->u1.isInterrupted = 1;
1561 }
1562 
1563 
1564 /*
1565 ** This function is exactly the same as sqlite3_create_function(), except
1566 ** that it is designed to be called by internal code. The difference is
1567 ** that if a malloc() fails in sqlite3_create_function(), an error code
1568 ** is returned and the mallocFailed flag cleared.
1569 */
1570 int sqlite3CreateFunc(
1571   sqlite3 *db,
1572   const char *zFunctionName,
1573   int nArg,
1574   int enc,
1575   void *pUserData,
1576   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1577   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1578   void (*xFinal)(sqlite3_context*),
1579   FuncDestructor *pDestructor
1580 ){
1581   FuncDef *p;
1582   int nName;
1583   int extraFlags;
1584 
1585   assert( sqlite3_mutex_held(db->mutex) );
1586   if( zFunctionName==0 ||
1587       (xSFunc && (xFinal || xStep)) ||
1588       (!xSFunc && (xFinal && !xStep)) ||
1589       (!xSFunc && (!xFinal && xStep)) ||
1590       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1591       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1592     return SQLITE_MISUSE_BKPT;
1593   }
1594 
1595   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1596   extraFlags = enc &  SQLITE_DETERMINISTIC;
1597   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1598 
1599 #ifndef SQLITE_OMIT_UTF16
1600   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1601   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1602   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1603   **
1604   ** If SQLITE_ANY is specified, add three versions of the function
1605   ** to the hash table.
1606   */
1607   if( enc==SQLITE_UTF16 ){
1608     enc = SQLITE_UTF16NATIVE;
1609   }else if( enc==SQLITE_ANY ){
1610     int rc;
1611     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1612          pUserData, xSFunc, xStep, xFinal, pDestructor);
1613     if( rc==SQLITE_OK ){
1614       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1615           pUserData, xSFunc, xStep, xFinal, pDestructor);
1616     }
1617     if( rc!=SQLITE_OK ){
1618       return rc;
1619     }
1620     enc = SQLITE_UTF16BE;
1621   }
1622 #else
1623   enc = SQLITE_UTF8;
1624 #endif
1625 
1626   /* Check if an existing function is being overridden or deleted. If so,
1627   ** and there are active VMs, then return SQLITE_BUSY. If a function
1628   ** is being overridden/deleted but there are no active VMs, allow the
1629   ** operation to continue but invalidate all precompiled statements.
1630   */
1631   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
1632   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==enc && p->nArg==nArg ){
1633     if( db->nVdbeActive ){
1634       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1635         "unable to delete/modify user-function due to active statements");
1636       assert( !db->mallocFailed );
1637       return SQLITE_BUSY;
1638     }else{
1639       sqlite3ExpirePreparedStatements(db);
1640     }
1641   }
1642 
1643   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
1644   assert(p || db->mallocFailed);
1645   if( !p ){
1646     return SQLITE_NOMEM_BKPT;
1647   }
1648 
1649   /* If an older version of the function with a configured destructor is
1650   ** being replaced invoke the destructor function here. */
1651   functionDestroy(db, p);
1652 
1653   if( pDestructor ){
1654     pDestructor->nRef++;
1655   }
1656   p->u.pDestructor = pDestructor;
1657   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1658   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1659   p->xSFunc = xSFunc ? xSFunc : xStep;
1660   p->xFinalize = xFinal;
1661   p->pUserData = pUserData;
1662   p->nArg = (u16)nArg;
1663   return SQLITE_OK;
1664 }
1665 
1666 /*
1667 ** Create new user functions.
1668 */
1669 int sqlite3_create_function(
1670   sqlite3 *db,
1671   const char *zFunc,
1672   int nArg,
1673   int enc,
1674   void *p,
1675   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1676   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1677   void (*xFinal)(sqlite3_context*)
1678 ){
1679   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xSFunc, xStep,
1680                                     xFinal, 0);
1681 }
1682 
1683 int sqlite3_create_function_v2(
1684   sqlite3 *db,
1685   const char *zFunc,
1686   int nArg,
1687   int enc,
1688   void *p,
1689   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1690   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1691   void (*xFinal)(sqlite3_context*),
1692   void (*xDestroy)(void *)
1693 ){
1694   int rc = SQLITE_ERROR;
1695   FuncDestructor *pArg = 0;
1696 
1697 #ifdef SQLITE_ENABLE_API_ARMOR
1698   if( !sqlite3SafetyCheckOk(db) ){
1699     return SQLITE_MISUSE_BKPT;
1700   }
1701 #endif
1702   sqlite3_mutex_enter(db->mutex);
1703   if( xDestroy ){
1704     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1705     if( !pArg ){
1706       xDestroy(p);
1707       goto out;
1708     }
1709     pArg->xDestroy = xDestroy;
1710     pArg->pUserData = p;
1711   }
1712   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xSFunc, xStep, xFinal, pArg);
1713   if( pArg && pArg->nRef==0 ){
1714     assert( rc!=SQLITE_OK );
1715     xDestroy(p);
1716     sqlite3DbFree(db, pArg);
1717   }
1718 
1719  out:
1720   rc = sqlite3ApiExit(db, rc);
1721   sqlite3_mutex_leave(db->mutex);
1722   return rc;
1723 }
1724 
1725 #ifndef SQLITE_OMIT_UTF16
1726 int sqlite3_create_function16(
1727   sqlite3 *db,
1728   const void *zFunctionName,
1729   int nArg,
1730   int eTextRep,
1731   void *p,
1732   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1733   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1734   void (*xFinal)(sqlite3_context*)
1735 ){
1736   int rc;
1737   char *zFunc8;
1738 
1739 #ifdef SQLITE_ENABLE_API_ARMOR
1740   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1741 #endif
1742   sqlite3_mutex_enter(db->mutex);
1743   assert( !db->mallocFailed );
1744   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1745   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0);
1746   sqlite3DbFree(db, zFunc8);
1747   rc = sqlite3ApiExit(db, rc);
1748   sqlite3_mutex_leave(db->mutex);
1749   return rc;
1750 }
1751 #endif
1752 
1753 
1754 /*
1755 ** Declare that a function has been overloaded by a virtual table.
1756 **
1757 ** If the function already exists as a regular global function, then
1758 ** this routine is a no-op.  If the function does not exist, then create
1759 ** a new one that always throws a run-time error.
1760 **
1761 ** When virtual tables intend to provide an overloaded function, they
1762 ** should call this routine to make sure the global function exists.
1763 ** A global function must exist in order for name resolution to work
1764 ** properly.
1765 */
1766 int sqlite3_overload_function(
1767   sqlite3 *db,
1768   const char *zName,
1769   int nArg
1770 ){
1771   int rc = SQLITE_OK;
1772 
1773 #ifdef SQLITE_ENABLE_API_ARMOR
1774   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1775     return SQLITE_MISUSE_BKPT;
1776   }
1777 #endif
1778   sqlite3_mutex_enter(db->mutex);
1779   if( sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)==0 ){
1780     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1781                            0, sqlite3InvalidFunction, 0, 0, 0);
1782   }
1783   rc = sqlite3ApiExit(db, rc);
1784   sqlite3_mutex_leave(db->mutex);
1785   return rc;
1786 }
1787 
1788 #ifndef SQLITE_OMIT_TRACE
1789 /*
1790 ** Register a trace function.  The pArg from the previously registered trace
1791 ** is returned.
1792 **
1793 ** A NULL trace function means that no tracing is executes.  A non-NULL
1794 ** trace is a pointer to a function that is invoked at the start of each
1795 ** SQL statement.
1796 */
1797 void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
1798   void *pOld;
1799 
1800 #ifdef SQLITE_ENABLE_API_ARMOR
1801   if( !sqlite3SafetyCheckOk(db) ){
1802     (void)SQLITE_MISUSE_BKPT;
1803     return 0;
1804   }
1805 #endif
1806   sqlite3_mutex_enter(db->mutex);
1807   pOld = db->pTraceArg;
1808   db->xTrace = xTrace;
1809   db->pTraceArg = pArg;
1810   sqlite3_mutex_leave(db->mutex);
1811   return pOld;
1812 }
1813 /*
1814 ** Register a profile function.  The pArg from the previously registered
1815 ** profile function is returned.
1816 **
1817 ** A NULL profile function means that no profiling is executes.  A non-NULL
1818 ** profile is a pointer to a function that is invoked at the conclusion of
1819 ** each SQL statement that is run.
1820 */
1821 void *sqlite3_profile(
1822   sqlite3 *db,
1823   void (*xProfile)(void*,const char*,sqlite_uint64),
1824   void *pArg
1825 ){
1826   void *pOld;
1827 
1828 #ifdef SQLITE_ENABLE_API_ARMOR
1829   if( !sqlite3SafetyCheckOk(db) ){
1830     (void)SQLITE_MISUSE_BKPT;
1831     return 0;
1832   }
1833 #endif
1834   sqlite3_mutex_enter(db->mutex);
1835   pOld = db->pProfileArg;
1836   db->xProfile = xProfile;
1837   db->pProfileArg = pArg;
1838   sqlite3_mutex_leave(db->mutex);
1839   return pOld;
1840 }
1841 #endif /* SQLITE_OMIT_TRACE */
1842 
1843 /*
1844 ** Register a function to be invoked when a transaction commits.
1845 ** If the invoked function returns non-zero, then the commit becomes a
1846 ** rollback.
1847 */
1848 void *sqlite3_commit_hook(
1849   sqlite3 *db,              /* Attach the hook to this database */
1850   int (*xCallback)(void*),  /* Function to invoke on each commit */
1851   void *pArg                /* Argument to the function */
1852 ){
1853   void *pOld;
1854 
1855 #ifdef SQLITE_ENABLE_API_ARMOR
1856   if( !sqlite3SafetyCheckOk(db) ){
1857     (void)SQLITE_MISUSE_BKPT;
1858     return 0;
1859   }
1860 #endif
1861   sqlite3_mutex_enter(db->mutex);
1862   pOld = db->pCommitArg;
1863   db->xCommitCallback = xCallback;
1864   db->pCommitArg = pArg;
1865   sqlite3_mutex_leave(db->mutex);
1866   return pOld;
1867 }
1868 
1869 /*
1870 ** Register a callback to be invoked each time a row is updated,
1871 ** inserted or deleted using this database connection.
1872 */
1873 void *sqlite3_update_hook(
1874   sqlite3 *db,              /* Attach the hook to this database */
1875   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
1876   void *pArg                /* Argument to the function */
1877 ){
1878   void *pRet;
1879 
1880 #ifdef SQLITE_ENABLE_API_ARMOR
1881   if( !sqlite3SafetyCheckOk(db) ){
1882     (void)SQLITE_MISUSE_BKPT;
1883     return 0;
1884   }
1885 #endif
1886   sqlite3_mutex_enter(db->mutex);
1887   pRet = db->pUpdateArg;
1888   db->xUpdateCallback = xCallback;
1889   db->pUpdateArg = pArg;
1890   sqlite3_mutex_leave(db->mutex);
1891   return pRet;
1892 }
1893 
1894 /*
1895 ** Register a callback to be invoked each time a transaction is rolled
1896 ** back by this database connection.
1897 */
1898 void *sqlite3_rollback_hook(
1899   sqlite3 *db,              /* Attach the hook to this database */
1900   void (*xCallback)(void*), /* Callback function */
1901   void *pArg                /* Argument to the function */
1902 ){
1903   void *pRet;
1904 
1905 #ifdef SQLITE_ENABLE_API_ARMOR
1906   if( !sqlite3SafetyCheckOk(db) ){
1907     (void)SQLITE_MISUSE_BKPT;
1908     return 0;
1909   }
1910 #endif
1911   sqlite3_mutex_enter(db->mutex);
1912   pRet = db->pRollbackArg;
1913   db->xRollbackCallback = xCallback;
1914   db->pRollbackArg = pArg;
1915   sqlite3_mutex_leave(db->mutex);
1916   return pRet;
1917 }
1918 
1919 #ifndef SQLITE_OMIT_WAL
1920 /*
1921 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
1922 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
1923 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
1924 ** wal_autocheckpoint()).
1925 */
1926 int sqlite3WalDefaultHook(
1927   void *pClientData,     /* Argument */
1928   sqlite3 *db,           /* Connection */
1929   const char *zDb,       /* Database */
1930   int nFrame             /* Size of WAL */
1931 ){
1932   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
1933     sqlite3BeginBenignMalloc();
1934     sqlite3_wal_checkpoint(db, zDb);
1935     sqlite3EndBenignMalloc();
1936   }
1937   return SQLITE_OK;
1938 }
1939 #endif /* SQLITE_OMIT_WAL */
1940 
1941 /*
1942 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
1943 ** a database after committing a transaction if there are nFrame or
1944 ** more frames in the log file. Passing zero or a negative value as the
1945 ** nFrame parameter disables automatic checkpoints entirely.
1946 **
1947 ** The callback registered by this function replaces any existing callback
1948 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
1949 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
1950 ** configured by this function.
1951 */
1952 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
1953 #ifdef SQLITE_OMIT_WAL
1954   UNUSED_PARAMETER(db);
1955   UNUSED_PARAMETER(nFrame);
1956 #else
1957 #ifdef SQLITE_ENABLE_API_ARMOR
1958   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1959 #endif
1960   if( nFrame>0 ){
1961     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
1962   }else{
1963     sqlite3_wal_hook(db, 0, 0);
1964   }
1965 #endif
1966   return SQLITE_OK;
1967 }
1968 
1969 /*
1970 ** Register a callback to be invoked each time a transaction is written
1971 ** into the write-ahead-log by this database connection.
1972 */
1973 void *sqlite3_wal_hook(
1974   sqlite3 *db,                    /* Attach the hook to this db handle */
1975   int(*xCallback)(void *, sqlite3*, const char*, int),
1976   void *pArg                      /* First argument passed to xCallback() */
1977 ){
1978 #ifndef SQLITE_OMIT_WAL
1979   void *pRet;
1980 #ifdef SQLITE_ENABLE_API_ARMOR
1981   if( !sqlite3SafetyCheckOk(db) ){
1982     (void)SQLITE_MISUSE_BKPT;
1983     return 0;
1984   }
1985 #endif
1986   sqlite3_mutex_enter(db->mutex);
1987   pRet = db->pWalArg;
1988   db->xWalCallback = xCallback;
1989   db->pWalArg = pArg;
1990   sqlite3_mutex_leave(db->mutex);
1991   return pRet;
1992 #else
1993   return 0;
1994 #endif
1995 }
1996 
1997 /*
1998 ** Checkpoint database zDb.
1999 */
2000 int sqlite3_wal_checkpoint_v2(
2001   sqlite3 *db,                    /* Database handle */
2002   const char *zDb,                /* Name of attached database (or NULL) */
2003   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2004   int *pnLog,                     /* OUT: Size of WAL log in frames */
2005   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2006 ){
2007 #ifdef SQLITE_OMIT_WAL
2008   return SQLITE_OK;
2009 #else
2010   int rc;                         /* Return code */
2011   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2012 
2013 #ifdef SQLITE_ENABLE_API_ARMOR
2014   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2015 #endif
2016 
2017   /* Initialize the output variables to -1 in case an error occurs. */
2018   if( pnLog ) *pnLog = -1;
2019   if( pnCkpt ) *pnCkpt = -1;
2020 
2021   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2022   assert( SQLITE_CHECKPOINT_FULL==1 );
2023   assert( SQLITE_CHECKPOINT_RESTART==2 );
2024   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2025   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2026     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2027     ** mode: */
2028     return SQLITE_MISUSE;
2029   }
2030 
2031   sqlite3_mutex_enter(db->mutex);
2032   if( zDb && zDb[0] ){
2033     iDb = sqlite3FindDbName(db, zDb);
2034   }
2035   if( iDb<0 ){
2036     rc = SQLITE_ERROR;
2037     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2038   }else{
2039     db->busyHandler.nBusy = 0;
2040     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2041     sqlite3Error(db, rc);
2042   }
2043   rc = sqlite3ApiExit(db, rc);
2044   sqlite3_mutex_leave(db->mutex);
2045   return rc;
2046 #endif
2047 }
2048 
2049 
2050 /*
2051 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2052 ** to contains a zero-length string, all attached databases are
2053 ** checkpointed.
2054 */
2055 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2056   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2057   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2058   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2059 }
2060 
2061 #ifndef SQLITE_OMIT_WAL
2062 /*
2063 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2064 ** not currently open in WAL mode.
2065 **
2066 ** If a transaction is open on the database being checkpointed, this
2067 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2068 ** an error occurs while running the checkpoint, an SQLite error code is
2069 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2070 **
2071 ** The mutex on database handle db should be held by the caller. The mutex
2072 ** associated with the specific b-tree being checkpointed is taken by
2073 ** this function while the checkpoint is running.
2074 **
2075 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2076 ** checkpointed. If an error is encountered it is returned immediately -
2077 ** no attempt is made to checkpoint any remaining databases.
2078 **
2079 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
2080 */
2081 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2082   int rc = SQLITE_OK;             /* Return code */
2083   int i;                          /* Used to iterate through attached dbs */
2084   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2085 
2086   assert( sqlite3_mutex_held(db->mutex) );
2087   assert( !pnLog || *pnLog==-1 );
2088   assert( !pnCkpt || *pnCkpt==-1 );
2089 
2090   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2091     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2092       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2093       pnLog = 0;
2094       pnCkpt = 0;
2095       if( rc==SQLITE_BUSY ){
2096         bBusy = 1;
2097         rc = SQLITE_OK;
2098       }
2099     }
2100   }
2101 
2102   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2103 }
2104 #endif /* SQLITE_OMIT_WAL */
2105 
2106 /*
2107 ** This function returns true if main-memory should be used instead of
2108 ** a temporary file for transient pager files and statement journals.
2109 ** The value returned depends on the value of db->temp_store (runtime
2110 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2111 ** following table describes the relationship between these two values
2112 ** and this functions return value.
2113 **
2114 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2115 **   -----------------     --------------     ------------------------------
2116 **   0                     any                file      (return 0)
2117 **   1                     1                  file      (return 0)
2118 **   1                     2                  memory    (return 1)
2119 **   1                     0                  file      (return 0)
2120 **   2                     1                  file      (return 0)
2121 **   2                     2                  memory    (return 1)
2122 **   2                     0                  memory    (return 1)
2123 **   3                     any                memory    (return 1)
2124 */
2125 int sqlite3TempInMemory(const sqlite3 *db){
2126 #if SQLITE_TEMP_STORE==1
2127   return ( db->temp_store==2 );
2128 #endif
2129 #if SQLITE_TEMP_STORE==2
2130   return ( db->temp_store!=1 );
2131 #endif
2132 #if SQLITE_TEMP_STORE==3
2133   UNUSED_PARAMETER(db);
2134   return 1;
2135 #endif
2136 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2137   UNUSED_PARAMETER(db);
2138   return 0;
2139 #endif
2140 }
2141 
2142 /*
2143 ** Return UTF-8 encoded English language explanation of the most recent
2144 ** error.
2145 */
2146 const char *sqlite3_errmsg(sqlite3 *db){
2147   const char *z;
2148   if( !db ){
2149     return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2150   }
2151   if( !sqlite3SafetyCheckSickOrOk(db) ){
2152     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2153   }
2154   sqlite3_mutex_enter(db->mutex);
2155   if( db->mallocFailed ){
2156     z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2157   }else{
2158     testcase( db->pErr==0 );
2159     z = (char*)sqlite3_value_text(db->pErr);
2160     assert( !db->mallocFailed );
2161     if( z==0 ){
2162       z = sqlite3ErrStr(db->errCode);
2163     }
2164   }
2165   sqlite3_mutex_leave(db->mutex);
2166   return z;
2167 }
2168 
2169 #ifndef SQLITE_OMIT_UTF16
2170 /*
2171 ** Return UTF-16 encoded English language explanation of the most recent
2172 ** error.
2173 */
2174 const void *sqlite3_errmsg16(sqlite3 *db){
2175   static const u16 outOfMem[] = {
2176     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2177   };
2178   static const u16 misuse[] = {
2179     'l', 'i', 'b', 'r', 'a', 'r', 'y', ' ',
2180     'r', 'o', 'u', 't', 'i', 'n', 'e', ' ',
2181     'c', 'a', 'l', 'l', 'e', 'd', ' ',
2182     'o', 'u', 't', ' ',
2183     'o', 'f', ' ',
2184     's', 'e', 'q', 'u', 'e', 'n', 'c', 'e', 0
2185   };
2186 
2187   const void *z;
2188   if( !db ){
2189     return (void *)outOfMem;
2190   }
2191   if( !sqlite3SafetyCheckSickOrOk(db) ){
2192     return (void *)misuse;
2193   }
2194   sqlite3_mutex_enter(db->mutex);
2195   if( db->mallocFailed ){
2196     z = (void *)outOfMem;
2197   }else{
2198     z = sqlite3_value_text16(db->pErr);
2199     if( z==0 ){
2200       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2201       z = sqlite3_value_text16(db->pErr);
2202     }
2203     /* A malloc() may have failed within the call to sqlite3_value_text16()
2204     ** above. If this is the case, then the db->mallocFailed flag needs to
2205     ** be cleared before returning. Do this directly, instead of via
2206     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2207     */
2208     sqlite3OomClear(db);
2209   }
2210   sqlite3_mutex_leave(db->mutex);
2211   return z;
2212 }
2213 #endif /* SQLITE_OMIT_UTF16 */
2214 
2215 /*
2216 ** Return the most recent error code generated by an SQLite routine. If NULL is
2217 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2218 */
2219 int sqlite3_errcode(sqlite3 *db){
2220   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2221     return SQLITE_MISUSE_BKPT;
2222   }
2223   if( !db || db->mallocFailed ){
2224     return SQLITE_NOMEM_BKPT;
2225   }
2226   return db->errCode & db->errMask;
2227 }
2228 int sqlite3_extended_errcode(sqlite3 *db){
2229   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2230     return SQLITE_MISUSE_BKPT;
2231   }
2232   if( !db || db->mallocFailed ){
2233     return SQLITE_NOMEM_BKPT;
2234   }
2235   return db->errCode;
2236 }
2237 
2238 /*
2239 ** Return a string that describes the kind of error specified in the
2240 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2241 ** function.
2242 */
2243 const char *sqlite3_errstr(int rc){
2244   return sqlite3ErrStr(rc);
2245 }
2246 
2247 /*
2248 ** Create a new collating function for database "db".  The name is zName
2249 ** and the encoding is enc.
2250 */
2251 static int createCollation(
2252   sqlite3* db,
2253   const char *zName,
2254   u8 enc,
2255   void* pCtx,
2256   int(*xCompare)(void*,int,const void*,int,const void*),
2257   void(*xDel)(void*)
2258 ){
2259   CollSeq *pColl;
2260   int enc2;
2261 
2262   assert( sqlite3_mutex_held(db->mutex) );
2263 
2264   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2265   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2266   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2267   */
2268   enc2 = enc;
2269   testcase( enc2==SQLITE_UTF16 );
2270   testcase( enc2==SQLITE_UTF16_ALIGNED );
2271   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2272     enc2 = SQLITE_UTF16NATIVE;
2273   }
2274   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2275     return SQLITE_MISUSE_BKPT;
2276   }
2277 
2278   /* Check if this call is removing or replacing an existing collation
2279   ** sequence. If so, and there are active VMs, return busy. If there
2280   ** are no active VMs, invalidate any pre-compiled statements.
2281   */
2282   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2283   if( pColl && pColl->xCmp ){
2284     if( db->nVdbeActive ){
2285       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2286         "unable to delete/modify collation sequence due to active statements");
2287       return SQLITE_BUSY;
2288     }
2289     sqlite3ExpirePreparedStatements(db);
2290 
2291     /* If collation sequence pColl was created directly by a call to
2292     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2293     ** then any copies made by synthCollSeq() need to be invalidated.
2294     ** Also, collation destructor - CollSeq.xDel() - function may need
2295     ** to be called.
2296     */
2297     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2298       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2299       int j;
2300       for(j=0; j<3; j++){
2301         CollSeq *p = &aColl[j];
2302         if( p->enc==pColl->enc ){
2303           if( p->xDel ){
2304             p->xDel(p->pUser);
2305           }
2306           p->xCmp = 0;
2307         }
2308       }
2309     }
2310   }
2311 
2312   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2313   if( pColl==0 ) return SQLITE_NOMEM_BKPT;
2314   pColl->xCmp = xCompare;
2315   pColl->pUser = pCtx;
2316   pColl->xDel = xDel;
2317   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2318   sqlite3Error(db, SQLITE_OK);
2319   return SQLITE_OK;
2320 }
2321 
2322 
2323 /*
2324 ** This array defines hard upper bounds on limit values.  The
2325 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2326 ** #defines in sqlite3.h.
2327 */
2328 static const int aHardLimit[] = {
2329   SQLITE_MAX_LENGTH,
2330   SQLITE_MAX_SQL_LENGTH,
2331   SQLITE_MAX_COLUMN,
2332   SQLITE_MAX_EXPR_DEPTH,
2333   SQLITE_MAX_COMPOUND_SELECT,
2334   SQLITE_MAX_VDBE_OP,
2335   SQLITE_MAX_FUNCTION_ARG,
2336   SQLITE_MAX_ATTACHED,
2337   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2338   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2339   SQLITE_MAX_TRIGGER_DEPTH,
2340   SQLITE_MAX_WORKER_THREADS,
2341 };
2342 
2343 /*
2344 ** Make sure the hard limits are set to reasonable values
2345 */
2346 #if SQLITE_MAX_LENGTH<100
2347 # error SQLITE_MAX_LENGTH must be at least 100
2348 #endif
2349 #if SQLITE_MAX_SQL_LENGTH<100
2350 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2351 #endif
2352 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2353 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2354 #endif
2355 #if SQLITE_MAX_COMPOUND_SELECT<2
2356 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2357 #endif
2358 #if SQLITE_MAX_VDBE_OP<40
2359 # error SQLITE_MAX_VDBE_OP must be at least 40
2360 #endif
2361 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>127
2362 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 127
2363 #endif
2364 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2365 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2366 #endif
2367 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2368 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2369 #endif
2370 #if SQLITE_MAX_COLUMN>32767
2371 # error SQLITE_MAX_COLUMN must not exceed 32767
2372 #endif
2373 #if SQLITE_MAX_TRIGGER_DEPTH<1
2374 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2375 #endif
2376 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2377 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2378 #endif
2379 
2380 
2381 /*
2382 ** Change the value of a limit.  Report the old value.
2383 ** If an invalid limit index is supplied, report -1.
2384 ** Make no changes but still report the old value if the
2385 ** new limit is negative.
2386 **
2387 ** A new lower limit does not shrink existing constructs.
2388 ** It merely prevents new constructs that exceed the limit
2389 ** from forming.
2390 */
2391 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2392   int oldLimit;
2393 
2394 #ifdef SQLITE_ENABLE_API_ARMOR
2395   if( !sqlite3SafetyCheckOk(db) ){
2396     (void)SQLITE_MISUSE_BKPT;
2397     return -1;
2398   }
2399 #endif
2400 
2401   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2402   ** there is a hard upper bound set at compile-time by a C preprocessor
2403   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2404   ** "_MAX_".)
2405   */
2406   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2407   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2408   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2409   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2410   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2411   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2412   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2413   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2414   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2415                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2416   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2417   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2418   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2419   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2420 
2421 
2422   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2423     return -1;
2424   }
2425   oldLimit = db->aLimit[limitId];
2426   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2427     if( newLimit>aHardLimit[limitId] ){
2428       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2429     }
2430     db->aLimit[limitId] = newLimit;
2431   }
2432   return oldLimit;                     /* IMP: R-53341-35419 */
2433 }
2434 
2435 /*
2436 ** This function is used to parse both URIs and non-URI filenames passed by the
2437 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2438 ** URIs specified as part of ATTACH statements.
2439 **
2440 ** The first argument to this function is the name of the VFS to use (or
2441 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2442 ** query parameter. The second argument contains the URI (or non-URI filename)
2443 ** itself. When this function is called the *pFlags variable should contain
2444 ** the default flags to open the database handle with. The value stored in
2445 ** *pFlags may be updated before returning if the URI filename contains
2446 ** "cache=xxx" or "mode=xxx" query parameters.
2447 **
2448 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2449 ** the VFS that should be used to open the database file. *pzFile is set to
2450 ** point to a buffer containing the name of the file to open. It is the
2451 ** responsibility of the caller to eventually call sqlite3_free() to release
2452 ** this buffer.
2453 **
2454 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2455 ** may be set to point to a buffer containing an English language error
2456 ** message. It is the responsibility of the caller to eventually release
2457 ** this buffer by calling sqlite3_free().
2458 */
2459 int sqlite3ParseUri(
2460   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2461   const char *zUri,               /* Nul-terminated URI to parse */
2462   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2463   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2464   char **pzFile,                  /* OUT: Filename component of URI */
2465   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2466 ){
2467   int rc = SQLITE_OK;
2468   unsigned int flags = *pFlags;
2469   const char *zVfs = zDefaultVfs;
2470   char *zFile;
2471   char c;
2472   int nUri = sqlite3Strlen30(zUri);
2473 
2474   assert( *pzErrMsg==0 );
2475 
2476   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2477             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2478    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2479   ){
2480     char *zOpt;
2481     int eState;                   /* Parser state when parsing URI */
2482     int iIn;                      /* Input character index */
2483     int iOut = 0;                 /* Output character index */
2484     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2485 
2486     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2487     ** method that there may be extra parameters following the file-name.  */
2488     flags |= SQLITE_OPEN_URI;
2489 
2490     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2491     zFile = sqlite3_malloc64(nByte);
2492     if( !zFile ) return SQLITE_NOMEM_BKPT;
2493 
2494     iIn = 5;
2495 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2496     if( strncmp(zUri+5, "///", 3)==0 ){
2497       iIn = 7;
2498       /* The following condition causes URIs with five leading / characters
2499       ** like file://///host/path to be converted into UNCs like //host/path.
2500       ** The correct URI for that UNC has only two or four leading / characters
2501       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2502       ** common error, we are told, so we handle it as a special case. */
2503       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2504     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2505       iIn = 16;
2506     }
2507 #else
2508     /* Discard the scheme and authority segments of the URI. */
2509     if( zUri[5]=='/' && zUri[6]=='/' ){
2510       iIn = 7;
2511       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2512       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2513         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2514             iIn-7, &zUri[7]);
2515         rc = SQLITE_ERROR;
2516         goto parse_uri_out;
2517       }
2518     }
2519 #endif
2520 
2521     /* Copy the filename and any query parameters into the zFile buffer.
2522     ** Decode %HH escape codes along the way.
2523     **
2524     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2525     ** on the parsing context. As follows:
2526     **
2527     **   0: Parsing file-name.
2528     **   1: Parsing name section of a name=value query parameter.
2529     **   2: Parsing value section of a name=value query parameter.
2530     */
2531     eState = 0;
2532     while( (c = zUri[iIn])!=0 && c!='#' ){
2533       iIn++;
2534       if( c=='%'
2535        && sqlite3Isxdigit(zUri[iIn])
2536        && sqlite3Isxdigit(zUri[iIn+1])
2537       ){
2538         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2539         octet += sqlite3HexToInt(zUri[iIn++]);
2540 
2541         assert( octet>=0 && octet<256 );
2542         if( octet==0 ){
2543           /* This branch is taken when "%00" appears within the URI. In this
2544           ** case we ignore all text in the remainder of the path, name or
2545           ** value currently being parsed. So ignore the current character
2546           ** and skip to the next "?", "=" or "&", as appropriate. */
2547           while( (c = zUri[iIn])!=0 && c!='#'
2548               && (eState!=0 || c!='?')
2549               && (eState!=1 || (c!='=' && c!='&'))
2550               && (eState!=2 || c!='&')
2551           ){
2552             iIn++;
2553           }
2554           continue;
2555         }
2556         c = octet;
2557       }else if( eState==1 && (c=='&' || c=='=') ){
2558         if( zFile[iOut-1]==0 ){
2559           /* An empty option name. Ignore this option altogether. */
2560           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2561           continue;
2562         }
2563         if( c=='&' ){
2564           zFile[iOut++] = '\0';
2565         }else{
2566           eState = 2;
2567         }
2568         c = 0;
2569       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2570         c = 0;
2571         eState = 1;
2572       }
2573       zFile[iOut++] = c;
2574     }
2575     if( eState==1 ) zFile[iOut++] = '\0';
2576     zFile[iOut++] = '\0';
2577     zFile[iOut++] = '\0';
2578 
2579     /* Check if there were any options specified that should be interpreted
2580     ** here. Options that are interpreted here include "vfs" and those that
2581     ** correspond to flags that may be passed to the sqlite3_open_v2()
2582     ** method. */
2583     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2584     while( zOpt[0] ){
2585       int nOpt = sqlite3Strlen30(zOpt);
2586       char *zVal = &zOpt[nOpt+1];
2587       int nVal = sqlite3Strlen30(zVal);
2588 
2589       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2590         zVfs = zVal;
2591       }else{
2592         struct OpenMode {
2593           const char *z;
2594           int mode;
2595         } *aMode = 0;
2596         char *zModeType = 0;
2597         int mask = 0;
2598         int limit = 0;
2599 
2600         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2601           static struct OpenMode aCacheMode[] = {
2602             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2603             { "private", SQLITE_OPEN_PRIVATECACHE },
2604             { 0, 0 }
2605           };
2606 
2607           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2608           aMode = aCacheMode;
2609           limit = mask;
2610           zModeType = "cache";
2611         }
2612         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2613           static struct OpenMode aOpenMode[] = {
2614             { "ro",  SQLITE_OPEN_READONLY },
2615             { "rw",  SQLITE_OPEN_READWRITE },
2616             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2617             { "memory", SQLITE_OPEN_MEMORY },
2618             { 0, 0 }
2619           };
2620 
2621           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2622                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2623           aMode = aOpenMode;
2624           limit = mask & flags;
2625           zModeType = "access";
2626         }
2627 
2628         if( aMode ){
2629           int i;
2630           int mode = 0;
2631           for(i=0; aMode[i].z; i++){
2632             const char *z = aMode[i].z;
2633             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2634               mode = aMode[i].mode;
2635               break;
2636             }
2637           }
2638           if( mode==0 ){
2639             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2640             rc = SQLITE_ERROR;
2641             goto parse_uri_out;
2642           }
2643           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2644             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2645                                         zModeType, zVal);
2646             rc = SQLITE_PERM;
2647             goto parse_uri_out;
2648           }
2649           flags = (flags & ~mask) | mode;
2650         }
2651       }
2652 
2653       zOpt = &zVal[nVal+1];
2654     }
2655 
2656   }else{
2657     zFile = sqlite3_malloc64(nUri+2);
2658     if( !zFile ) return SQLITE_NOMEM_BKPT;
2659     memcpy(zFile, zUri, nUri);
2660     zFile[nUri] = '\0';
2661     zFile[nUri+1] = '\0';
2662     flags &= ~SQLITE_OPEN_URI;
2663   }
2664 
2665   *ppVfs = sqlite3_vfs_find(zVfs);
2666   if( *ppVfs==0 ){
2667     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2668     rc = SQLITE_ERROR;
2669   }
2670  parse_uri_out:
2671   if( rc!=SQLITE_OK ){
2672     sqlite3_free(zFile);
2673     zFile = 0;
2674   }
2675   *pFlags = flags;
2676   *pzFile = zFile;
2677   return rc;
2678 }
2679 
2680 
2681 /*
2682 ** This routine does the work of opening a database on behalf of
2683 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2684 ** is UTF-8 encoded.
2685 */
2686 static int openDatabase(
2687   const char *zFilename, /* Database filename UTF-8 encoded */
2688   sqlite3 **ppDb,        /* OUT: Returned database handle */
2689   unsigned int flags,    /* Operational flags */
2690   const char *zVfs       /* Name of the VFS to use */
2691 ){
2692   sqlite3 *db;                    /* Store allocated handle here */
2693   int rc;                         /* Return code */
2694   int isThreadsafe;               /* True for threadsafe connections */
2695   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2696   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2697 
2698 #ifdef SQLITE_ENABLE_API_ARMOR
2699   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2700 #endif
2701   *ppDb = 0;
2702 #ifndef SQLITE_OMIT_AUTOINIT
2703   rc = sqlite3_initialize();
2704   if( rc ) return rc;
2705 #endif
2706 
2707   /* Only allow sensible combinations of bits in the flags argument.
2708   ** Throw an error if any non-sense combination is used.  If we
2709   ** do not block illegal combinations here, it could trigger
2710   ** assert() statements in deeper layers.  Sensible combinations
2711   ** are:
2712   **
2713   **  1:  SQLITE_OPEN_READONLY
2714   **  2:  SQLITE_OPEN_READWRITE
2715   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
2716   */
2717   assert( SQLITE_OPEN_READONLY  == 0x01 );
2718   assert( SQLITE_OPEN_READWRITE == 0x02 );
2719   assert( SQLITE_OPEN_CREATE    == 0x04 );
2720   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
2721   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
2722   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
2723   if( ((1<<(flags&7)) & 0x46)==0 ){
2724     return SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
2725   }
2726 
2727   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2728     isThreadsafe = 0;
2729   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2730     isThreadsafe = 0;
2731   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2732     isThreadsafe = 1;
2733   }else{
2734     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2735   }
2736   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2737     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2738   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2739     flags |= SQLITE_OPEN_SHAREDCACHE;
2740   }
2741 
2742   /* Remove harmful bits from the flags parameter
2743   **
2744   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2745   ** dealt with in the previous code block.  Besides these, the only
2746   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2747   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2748   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2749   ** off all other flags.
2750   */
2751   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2752                SQLITE_OPEN_EXCLUSIVE |
2753                SQLITE_OPEN_MAIN_DB |
2754                SQLITE_OPEN_TEMP_DB |
2755                SQLITE_OPEN_TRANSIENT_DB |
2756                SQLITE_OPEN_MAIN_JOURNAL |
2757                SQLITE_OPEN_TEMP_JOURNAL |
2758                SQLITE_OPEN_SUBJOURNAL |
2759                SQLITE_OPEN_MASTER_JOURNAL |
2760                SQLITE_OPEN_NOMUTEX |
2761                SQLITE_OPEN_FULLMUTEX |
2762                SQLITE_OPEN_WAL
2763              );
2764 
2765   /* Allocate the sqlite data structure */
2766   db = sqlite3MallocZero( sizeof(sqlite3) );
2767   if( db==0 ) goto opendb_out;
2768   if( isThreadsafe ){
2769     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2770     if( db->mutex==0 ){
2771       sqlite3_free(db);
2772       db = 0;
2773       goto opendb_out;
2774     }
2775   }
2776   sqlite3_mutex_enter(db->mutex);
2777   db->errMask = 0xff;
2778   db->nDb = 2;
2779   db->magic = SQLITE_MAGIC_BUSY;
2780   db->aDb = db->aDbStatic;
2781 
2782   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2783   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2784   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
2785   db->autoCommit = 1;
2786   db->nextAutovac = -1;
2787   db->szMmap = sqlite3GlobalConfig.szMmap;
2788   db->nextPagesize = 0;
2789   db->nMaxSorterMmap = 0x7FFFFFFF;
2790   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
2791 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2792                  | SQLITE_AutoIndex
2793 #endif
2794 #if SQLITE_DEFAULT_CKPTFULLFSYNC
2795                  | SQLITE_CkptFullFSync
2796 #endif
2797 #if SQLITE_DEFAULT_FILE_FORMAT<4
2798                  | SQLITE_LegacyFileFmt
2799 #endif
2800 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2801                  | SQLITE_LoadExtension
2802 #endif
2803 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2804                  | SQLITE_RecTriggers
2805 #endif
2806 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2807                  | SQLITE_ForeignKeys
2808 #endif
2809 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
2810                  | SQLITE_ReverseOrder
2811 #endif
2812 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
2813                  | SQLITE_CellSizeCk
2814 #endif
2815       ;
2816   sqlite3HashInit(&db->aCollSeq);
2817 #ifndef SQLITE_OMIT_VIRTUALTABLE
2818   sqlite3HashInit(&db->aModule);
2819 #endif
2820 
2821   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2822   ** and UTF-16, so add a version for each to avoid any unnecessary
2823   ** conversions. The only error that can occur here is a malloc() failure.
2824   **
2825   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
2826   ** functions:
2827   */
2828   createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
2829   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
2830   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
2831   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
2832   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
2833   if( db->mallocFailed ){
2834     goto opendb_out;
2835   }
2836   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
2837   ** strings is BINARY.
2838   */
2839   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, sqlite3StrBINARY, 0);
2840   assert( db->pDfltColl!=0 );
2841 
2842   /* Parse the filename/URI argument. */
2843   db->openFlags = flags;
2844   rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
2845   if( rc!=SQLITE_OK ){
2846     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
2847     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
2848     sqlite3_free(zErrMsg);
2849     goto opendb_out;
2850   }
2851 
2852   /* Open the backend database driver */
2853   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
2854                         flags | SQLITE_OPEN_MAIN_DB);
2855   if( rc!=SQLITE_OK ){
2856     if( rc==SQLITE_IOERR_NOMEM ){
2857       rc = SQLITE_NOMEM_BKPT;
2858     }
2859     sqlite3Error(db, rc);
2860     goto opendb_out;
2861   }
2862   sqlite3BtreeEnter(db->aDb[0].pBt);
2863   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
2864   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
2865   sqlite3BtreeLeave(db->aDb[0].pBt);
2866   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
2867 
2868   /* The default safety_level for the main database is FULL; for the temp
2869   ** database it is OFF. This matches the pager layer defaults.
2870   */
2871   db->aDb[0].zName = "main";
2872   db->aDb[0].safety_level = PAGER_SYNCHRONOUS_FULL;
2873   db->aDb[1].zName = "temp";
2874   db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
2875 
2876   db->magic = SQLITE_MAGIC_OPEN;
2877   if( db->mallocFailed ){
2878     goto opendb_out;
2879   }
2880 
2881   /* Register all built-in functions, but do not attempt to read the
2882   ** database schema yet. This is delayed until the first time the database
2883   ** is accessed.
2884   */
2885   sqlite3Error(db, SQLITE_OK);
2886   sqlite3RegisterPerConnectionBuiltinFunctions(db);
2887 
2888   /* Load automatic extensions - extensions that have been registered
2889   ** using the sqlite3_automatic_extension() API.
2890   */
2891   rc = sqlite3_errcode(db);
2892   if( rc==SQLITE_OK ){
2893     sqlite3AutoLoadExtensions(db);
2894     rc = sqlite3_errcode(db);
2895     if( rc!=SQLITE_OK ){
2896       goto opendb_out;
2897     }
2898   }
2899 
2900 #ifdef SQLITE_ENABLE_FTS1
2901   if( !db->mallocFailed ){
2902     extern int sqlite3Fts1Init(sqlite3*);
2903     rc = sqlite3Fts1Init(db);
2904   }
2905 #endif
2906 
2907 #ifdef SQLITE_ENABLE_FTS2
2908   if( !db->mallocFailed && rc==SQLITE_OK ){
2909     extern int sqlite3Fts2Init(sqlite3*);
2910     rc = sqlite3Fts2Init(db);
2911   }
2912 #endif
2913 
2914 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
2915   if( !db->mallocFailed && rc==SQLITE_OK ){
2916     rc = sqlite3Fts3Init(db);
2917   }
2918 #endif
2919 
2920 #ifdef SQLITE_ENABLE_FTS5
2921   if( !db->mallocFailed && rc==SQLITE_OK ){
2922     rc = sqlite3Fts5Init(db);
2923   }
2924 #endif
2925 
2926 #ifdef SQLITE_ENABLE_ICU
2927   if( !db->mallocFailed && rc==SQLITE_OK ){
2928     rc = sqlite3IcuInit(db);
2929   }
2930 #endif
2931 
2932 #ifdef SQLITE_ENABLE_RTREE
2933   if( !db->mallocFailed && rc==SQLITE_OK){
2934     rc = sqlite3RtreeInit(db);
2935   }
2936 #endif
2937 
2938 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
2939   if( !db->mallocFailed && rc==SQLITE_OK){
2940     rc = sqlite3DbstatRegister(db);
2941   }
2942 #endif
2943 
2944 #ifdef SQLITE_ENABLE_JSON1
2945   if( !db->mallocFailed && rc==SQLITE_OK){
2946     rc = sqlite3Json1Init(db);
2947   }
2948 #endif
2949 
2950   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
2951   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
2952   ** mode.  Doing nothing at all also makes NORMAL the default.
2953   */
2954 #ifdef SQLITE_DEFAULT_LOCKING_MODE
2955   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
2956   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
2957                           SQLITE_DEFAULT_LOCKING_MODE);
2958 #endif
2959 
2960   if( rc ) sqlite3Error(db, rc);
2961 
2962   /* Enable the lookaside-malloc subsystem */
2963   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
2964                         sqlite3GlobalConfig.nLookaside);
2965 
2966   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
2967 
2968 opendb_out:
2969   if( db ){
2970     assert( db->mutex!=0 || isThreadsafe==0
2971            || sqlite3GlobalConfig.bFullMutex==0 );
2972     sqlite3_mutex_leave(db->mutex);
2973   }
2974   rc = sqlite3_errcode(db);
2975   assert( db!=0 || rc==SQLITE_NOMEM );
2976   if( rc==SQLITE_NOMEM ){
2977     sqlite3_close(db);
2978     db = 0;
2979   }else if( rc!=SQLITE_OK ){
2980     db->magic = SQLITE_MAGIC_SICK;
2981   }
2982   *ppDb = db;
2983 #ifdef SQLITE_ENABLE_SQLLOG
2984   if( sqlite3GlobalConfig.xSqllog ){
2985     /* Opening a db handle. Fourth parameter is passed 0. */
2986     void *pArg = sqlite3GlobalConfig.pSqllogArg;
2987     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
2988   }
2989 #endif
2990 #if defined(SQLITE_HAS_CODEC)
2991   if( rc==SQLITE_OK ){
2992     const char *zHexKey = sqlite3_uri_parameter(zOpen, "hexkey");
2993     if( zHexKey && zHexKey[0] ){
2994       u8 iByte;
2995       int i;
2996       char zKey[40];
2997       for(i=0, iByte=0; i<sizeof(zKey)*2 && sqlite3Isxdigit(zHexKey[i]); i++){
2998         iByte = (iByte<<4) + sqlite3HexToInt(zHexKey[i]);
2999         if( (i&1)!=0 ) zKey[i/2] = iByte;
3000       }
3001       sqlite3_key_v2(db, 0, zKey, i/2);
3002     }
3003   }
3004 #endif
3005   sqlite3_free(zOpen);
3006   return rc & 0xff;
3007 }
3008 
3009 /*
3010 ** Open a new database handle.
3011 */
3012 int sqlite3_open(
3013   const char *zFilename,
3014   sqlite3 **ppDb
3015 ){
3016   return openDatabase(zFilename, ppDb,
3017                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3018 }
3019 int sqlite3_open_v2(
3020   const char *filename,   /* Database filename (UTF-8) */
3021   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3022   int flags,              /* Flags */
3023   const char *zVfs        /* Name of VFS module to use */
3024 ){
3025   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3026 }
3027 
3028 #ifndef SQLITE_OMIT_UTF16
3029 /*
3030 ** Open a new database handle.
3031 */
3032 int sqlite3_open16(
3033   const void *zFilename,
3034   sqlite3 **ppDb
3035 ){
3036   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3037   sqlite3_value *pVal;
3038   int rc;
3039 
3040 #ifdef SQLITE_ENABLE_API_ARMOR
3041   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3042 #endif
3043   *ppDb = 0;
3044 #ifndef SQLITE_OMIT_AUTOINIT
3045   rc = sqlite3_initialize();
3046   if( rc ) return rc;
3047 #endif
3048   if( zFilename==0 ) zFilename = "\000\000";
3049   pVal = sqlite3ValueNew(0);
3050   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3051   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3052   if( zFilename8 ){
3053     rc = openDatabase(zFilename8, ppDb,
3054                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3055     assert( *ppDb || rc==SQLITE_NOMEM );
3056     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3057       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3058     }
3059   }else{
3060     rc = SQLITE_NOMEM_BKPT;
3061   }
3062   sqlite3ValueFree(pVal);
3063 
3064   return rc & 0xff;
3065 }
3066 #endif /* SQLITE_OMIT_UTF16 */
3067 
3068 /*
3069 ** Register a new collation sequence with the database handle db.
3070 */
3071 int sqlite3_create_collation(
3072   sqlite3* db,
3073   const char *zName,
3074   int enc,
3075   void* pCtx,
3076   int(*xCompare)(void*,int,const void*,int,const void*)
3077 ){
3078   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3079 }
3080 
3081 /*
3082 ** Register a new collation sequence with the database handle db.
3083 */
3084 int sqlite3_create_collation_v2(
3085   sqlite3* db,
3086   const char *zName,
3087   int enc,
3088   void* pCtx,
3089   int(*xCompare)(void*,int,const void*,int,const void*),
3090   void(*xDel)(void*)
3091 ){
3092   int rc;
3093 
3094 #ifdef SQLITE_ENABLE_API_ARMOR
3095   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3096 #endif
3097   sqlite3_mutex_enter(db->mutex);
3098   assert( !db->mallocFailed );
3099   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3100   rc = sqlite3ApiExit(db, rc);
3101   sqlite3_mutex_leave(db->mutex);
3102   return rc;
3103 }
3104 
3105 #ifndef SQLITE_OMIT_UTF16
3106 /*
3107 ** Register a new collation sequence with the database handle db.
3108 */
3109 int sqlite3_create_collation16(
3110   sqlite3* db,
3111   const void *zName,
3112   int enc,
3113   void* pCtx,
3114   int(*xCompare)(void*,int,const void*,int,const void*)
3115 ){
3116   int rc = SQLITE_OK;
3117   char *zName8;
3118 
3119 #ifdef SQLITE_ENABLE_API_ARMOR
3120   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3121 #endif
3122   sqlite3_mutex_enter(db->mutex);
3123   assert( !db->mallocFailed );
3124   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3125   if( zName8 ){
3126     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3127     sqlite3DbFree(db, zName8);
3128   }
3129   rc = sqlite3ApiExit(db, rc);
3130   sqlite3_mutex_leave(db->mutex);
3131   return rc;
3132 }
3133 #endif /* SQLITE_OMIT_UTF16 */
3134 
3135 /*
3136 ** Register a collation sequence factory callback with the database handle
3137 ** db. Replace any previously installed collation sequence factory.
3138 */
3139 int sqlite3_collation_needed(
3140   sqlite3 *db,
3141   void *pCollNeededArg,
3142   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3143 ){
3144 #ifdef SQLITE_ENABLE_API_ARMOR
3145   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3146 #endif
3147   sqlite3_mutex_enter(db->mutex);
3148   db->xCollNeeded = xCollNeeded;
3149   db->xCollNeeded16 = 0;
3150   db->pCollNeededArg = pCollNeededArg;
3151   sqlite3_mutex_leave(db->mutex);
3152   return SQLITE_OK;
3153 }
3154 
3155 #ifndef SQLITE_OMIT_UTF16
3156 /*
3157 ** Register a collation sequence factory callback with the database handle
3158 ** db. Replace any previously installed collation sequence factory.
3159 */
3160 int sqlite3_collation_needed16(
3161   sqlite3 *db,
3162   void *pCollNeededArg,
3163   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3164 ){
3165 #ifdef SQLITE_ENABLE_API_ARMOR
3166   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3167 #endif
3168   sqlite3_mutex_enter(db->mutex);
3169   db->xCollNeeded = 0;
3170   db->xCollNeeded16 = xCollNeeded16;
3171   db->pCollNeededArg = pCollNeededArg;
3172   sqlite3_mutex_leave(db->mutex);
3173   return SQLITE_OK;
3174 }
3175 #endif /* SQLITE_OMIT_UTF16 */
3176 
3177 #ifndef SQLITE_OMIT_DEPRECATED
3178 /*
3179 ** This function is now an anachronism. It used to be used to recover from a
3180 ** malloc() failure, but SQLite now does this automatically.
3181 */
3182 int sqlite3_global_recover(void){
3183   return SQLITE_OK;
3184 }
3185 #endif
3186 
3187 /*
3188 ** Test to see whether or not the database connection is in autocommit
3189 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3190 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3191 ** by the next COMMIT or ROLLBACK.
3192 */
3193 int sqlite3_get_autocommit(sqlite3 *db){
3194 #ifdef SQLITE_ENABLE_API_ARMOR
3195   if( !sqlite3SafetyCheckOk(db) ){
3196     (void)SQLITE_MISUSE_BKPT;
3197     return 0;
3198   }
3199 #endif
3200   return db->autoCommit;
3201 }
3202 
3203 /*
3204 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3205 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
3206 ** constants.  They serve two purposes:
3207 **
3208 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3209 **       to detect when version error conditions occurs.
3210 **
3211 **   2.  Invoke sqlite3_log() to provide the source code location where
3212 **       a low-level error is first detected.
3213 */
3214 static int reportError(int iErr, int lineno, const char *zType){
3215   sqlite3_log(iErr, "%s at line %d of [%.10s]",
3216               zType, lineno, 20+sqlite3_sourceid());
3217   return iErr;
3218 }
3219 int sqlite3CorruptError(int lineno){
3220   testcase( sqlite3GlobalConfig.xLog!=0 );
3221   return reportError(SQLITE_CORRUPT, lineno, "database corruption");
3222 }
3223 int sqlite3MisuseError(int lineno){
3224   testcase( sqlite3GlobalConfig.xLog!=0 );
3225   return reportError(SQLITE_MISUSE, lineno, "misuse");
3226 }
3227 int sqlite3CantopenError(int lineno){
3228   testcase( sqlite3GlobalConfig.xLog!=0 );
3229   return reportError(SQLITE_CANTOPEN, lineno, "cannot open file");
3230 }
3231 #ifdef SQLITE_DEBUG
3232 int sqlite3NomemError(int lineno){
3233   testcase( sqlite3GlobalConfig.xLog!=0 );
3234   return reportError(SQLITE_NOMEM, lineno, "OOM");
3235 }
3236 int sqlite3IoerrnomemError(int lineno){
3237   testcase( sqlite3GlobalConfig.xLog!=0 );
3238   return reportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
3239 }
3240 #endif
3241 
3242 #ifndef SQLITE_OMIT_DEPRECATED
3243 /*
3244 ** This is a convenience routine that makes sure that all thread-specific
3245 ** data for this thread has been deallocated.
3246 **
3247 ** SQLite no longer uses thread-specific data so this routine is now a
3248 ** no-op.  It is retained for historical compatibility.
3249 */
3250 void sqlite3_thread_cleanup(void){
3251 }
3252 #endif
3253 
3254 /*
3255 ** Return meta information about a specific column of a database table.
3256 ** See comment in sqlite3.h (sqlite.h.in) for details.
3257 */
3258 int sqlite3_table_column_metadata(
3259   sqlite3 *db,                /* Connection handle */
3260   const char *zDbName,        /* Database name or NULL */
3261   const char *zTableName,     /* Table name */
3262   const char *zColumnName,    /* Column name */
3263   char const **pzDataType,    /* OUTPUT: Declared data type */
3264   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3265   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3266   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3267   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3268 ){
3269   int rc;
3270   char *zErrMsg = 0;
3271   Table *pTab = 0;
3272   Column *pCol = 0;
3273   int iCol = 0;
3274   char const *zDataType = 0;
3275   char const *zCollSeq = 0;
3276   int notnull = 0;
3277   int primarykey = 0;
3278   int autoinc = 0;
3279 
3280 
3281 #ifdef SQLITE_ENABLE_API_ARMOR
3282   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3283     return SQLITE_MISUSE_BKPT;
3284   }
3285 #endif
3286 
3287   /* Ensure the database schema has been loaded */
3288   sqlite3_mutex_enter(db->mutex);
3289   sqlite3BtreeEnterAll(db);
3290   rc = sqlite3Init(db, &zErrMsg);
3291   if( SQLITE_OK!=rc ){
3292     goto error_out;
3293   }
3294 
3295   /* Locate the table in question */
3296   pTab = sqlite3FindTable(db, zTableName, zDbName);
3297   if( !pTab || pTab->pSelect ){
3298     pTab = 0;
3299     goto error_out;
3300   }
3301 
3302   /* Find the column for which info is requested */
3303   if( zColumnName==0 ){
3304     /* Query for existance of table only */
3305   }else{
3306     for(iCol=0; iCol<pTab->nCol; iCol++){
3307       pCol = &pTab->aCol[iCol];
3308       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3309         break;
3310       }
3311     }
3312     if( iCol==pTab->nCol ){
3313       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3314         iCol = pTab->iPKey;
3315         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3316       }else{
3317         pTab = 0;
3318         goto error_out;
3319       }
3320     }
3321   }
3322 
3323   /* The following block stores the meta information that will be returned
3324   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3325   ** and autoinc. At this point there are two possibilities:
3326   **
3327   **     1. The specified column name was rowid", "oid" or "_rowid_"
3328   **        and there is no explicitly declared IPK column.
3329   **
3330   **     2. The table is not a view and the column name identified an
3331   **        explicitly declared column. Copy meta information from *pCol.
3332   */
3333   if( pCol ){
3334     zDataType = pCol->zType;
3335     zCollSeq = pCol->zColl;
3336     notnull = pCol->notNull!=0;
3337     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3338     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3339   }else{
3340     zDataType = "INTEGER";
3341     primarykey = 1;
3342   }
3343   if( !zCollSeq ){
3344     zCollSeq = sqlite3StrBINARY;
3345   }
3346 
3347 error_out:
3348   sqlite3BtreeLeaveAll(db);
3349 
3350   /* Whether the function call succeeded or failed, set the output parameters
3351   ** to whatever their local counterparts contain. If an error did occur,
3352   ** this has the effect of zeroing all output parameters.
3353   */
3354   if( pzDataType ) *pzDataType = zDataType;
3355   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3356   if( pNotNull ) *pNotNull = notnull;
3357   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3358   if( pAutoinc ) *pAutoinc = autoinc;
3359 
3360   if( SQLITE_OK==rc && !pTab ){
3361     sqlite3DbFree(db, zErrMsg);
3362     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3363         zColumnName);
3364     rc = SQLITE_ERROR;
3365   }
3366   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3367   sqlite3DbFree(db, zErrMsg);
3368   rc = sqlite3ApiExit(db, rc);
3369   sqlite3_mutex_leave(db->mutex);
3370   return rc;
3371 }
3372 
3373 /*
3374 ** Sleep for a little while.  Return the amount of time slept.
3375 */
3376 int sqlite3_sleep(int ms){
3377   sqlite3_vfs *pVfs;
3378   int rc;
3379   pVfs = sqlite3_vfs_find(0);
3380   if( pVfs==0 ) return 0;
3381 
3382   /* This function works in milliseconds, but the underlying OsSleep()
3383   ** API uses microseconds. Hence the 1000's.
3384   */
3385   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3386   return rc;
3387 }
3388 
3389 /*
3390 ** Enable or disable the extended result codes.
3391 */
3392 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3393 #ifdef SQLITE_ENABLE_API_ARMOR
3394   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3395 #endif
3396   sqlite3_mutex_enter(db->mutex);
3397   db->errMask = onoff ? 0xffffffff : 0xff;
3398   sqlite3_mutex_leave(db->mutex);
3399   return SQLITE_OK;
3400 }
3401 
3402 /*
3403 ** Invoke the xFileControl method on a particular database.
3404 */
3405 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3406   int rc = SQLITE_ERROR;
3407   Btree *pBtree;
3408 
3409 #ifdef SQLITE_ENABLE_API_ARMOR
3410   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3411 #endif
3412   sqlite3_mutex_enter(db->mutex);
3413   pBtree = sqlite3DbNameToBtree(db, zDbName);
3414   if( pBtree ){
3415     Pager *pPager;
3416     sqlite3_file *fd;
3417     sqlite3BtreeEnter(pBtree);
3418     pPager = sqlite3BtreePager(pBtree);
3419     assert( pPager!=0 );
3420     fd = sqlite3PagerFile(pPager);
3421     assert( fd!=0 );
3422     if( op==SQLITE_FCNTL_FILE_POINTER ){
3423       *(sqlite3_file**)pArg = fd;
3424       rc = SQLITE_OK;
3425     }else if( op==SQLITE_FCNTL_VFS_POINTER ){
3426       *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
3427       rc = SQLITE_OK;
3428     }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
3429       *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
3430       rc = SQLITE_OK;
3431     }else if( fd->pMethods ){
3432       rc = sqlite3OsFileControl(fd, op, pArg);
3433     }else{
3434       rc = SQLITE_NOTFOUND;
3435     }
3436     sqlite3BtreeLeave(pBtree);
3437   }
3438   sqlite3_mutex_leave(db->mutex);
3439   return rc;
3440 }
3441 
3442 /*
3443 ** Interface to the testing logic.
3444 */
3445 int sqlite3_test_control(int op, ...){
3446   int rc = 0;
3447 #ifdef SQLITE_OMIT_BUILTIN_TEST
3448   UNUSED_PARAMETER(op);
3449 #else
3450   va_list ap;
3451   va_start(ap, op);
3452   switch( op ){
3453 
3454     /*
3455     ** Save the current state of the PRNG.
3456     */
3457     case SQLITE_TESTCTRL_PRNG_SAVE: {
3458       sqlite3PrngSaveState();
3459       break;
3460     }
3461 
3462     /*
3463     ** Restore the state of the PRNG to the last state saved using
3464     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3465     ** this verb acts like PRNG_RESET.
3466     */
3467     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3468       sqlite3PrngRestoreState();
3469       break;
3470     }
3471 
3472     /*
3473     ** Reset the PRNG back to its uninitialized state.  The next call
3474     ** to sqlite3_randomness() will reseed the PRNG using a single call
3475     ** to the xRandomness method of the default VFS.
3476     */
3477     case SQLITE_TESTCTRL_PRNG_RESET: {
3478       sqlite3_randomness(0,0);
3479       break;
3480     }
3481 
3482     /*
3483     **  sqlite3_test_control(BITVEC_TEST, size, program)
3484     **
3485     ** Run a test against a Bitvec object of size.  The program argument
3486     ** is an array of integers that defines the test.  Return -1 on a
3487     ** memory allocation error, 0 on success, or non-zero for an error.
3488     ** See the sqlite3BitvecBuiltinTest() for additional information.
3489     */
3490     case SQLITE_TESTCTRL_BITVEC_TEST: {
3491       int sz = va_arg(ap, int);
3492       int *aProg = va_arg(ap, int*);
3493       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3494       break;
3495     }
3496 
3497     /*
3498     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3499     **
3500     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3501     ** if xCallback is not NULL.
3502     **
3503     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3504     ** is called immediately after installing the new callback and the return
3505     ** value from sqlite3FaultSim(0) becomes the return from
3506     ** sqlite3_test_control().
3507     */
3508     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3509       /* MSVC is picky about pulling func ptrs from va lists.
3510       ** http://support.microsoft.com/kb/47961
3511       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3512       */
3513       typedef int(*TESTCALLBACKFUNC_t)(int);
3514       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3515       rc = sqlite3FaultSim(0);
3516       break;
3517     }
3518 
3519     /*
3520     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3521     **
3522     ** Register hooks to call to indicate which malloc() failures
3523     ** are benign.
3524     */
3525     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3526       typedef void (*void_function)(void);
3527       void_function xBenignBegin;
3528       void_function xBenignEnd;
3529       xBenignBegin = va_arg(ap, void_function);
3530       xBenignEnd = va_arg(ap, void_function);
3531       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3532       break;
3533     }
3534 
3535     /*
3536     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3537     **
3538     ** Set the PENDING byte to the value in the argument, if X>0.
3539     ** Make no changes if X==0.  Return the value of the pending byte
3540     ** as it existing before this routine was called.
3541     **
3542     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3543     ** an incompatible database file format.  Changing the PENDING byte
3544     ** while any database connection is open results in undefined and
3545     ** deleterious behavior.
3546     */
3547     case SQLITE_TESTCTRL_PENDING_BYTE: {
3548       rc = PENDING_BYTE;
3549 #ifndef SQLITE_OMIT_WSD
3550       {
3551         unsigned int newVal = va_arg(ap, unsigned int);
3552         if( newVal ) sqlite3PendingByte = newVal;
3553       }
3554 #endif
3555       break;
3556     }
3557 
3558     /*
3559     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3560     **
3561     ** This action provides a run-time test to see whether or not
3562     ** assert() was enabled at compile-time.  If X is true and assert()
3563     ** is enabled, then the return value is true.  If X is true and
3564     ** assert() is disabled, then the return value is zero.  If X is
3565     ** false and assert() is enabled, then the assertion fires and the
3566     ** process aborts.  If X is false and assert() is disabled, then the
3567     ** return value is zero.
3568     */
3569     case SQLITE_TESTCTRL_ASSERT: {
3570       volatile int x = 0;
3571       assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
3572       rc = x;
3573       break;
3574     }
3575 
3576 
3577     /*
3578     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3579     **
3580     ** This action provides a run-time test to see how the ALWAYS and
3581     ** NEVER macros were defined at compile-time.
3582     **
3583     ** The return value is ALWAYS(X).
3584     **
3585     ** The recommended test is X==2.  If the return value is 2, that means
3586     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3587     ** default setting.  If the return value is 1, then ALWAYS() is either
3588     ** hard-coded to true or else it asserts if its argument is false.
3589     ** The first behavior (hard-coded to true) is the case if
3590     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3591     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3592     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3593     **
3594     ** The run-time test procedure might look something like this:
3595     **
3596     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3597     **      // ALWAYS() and NEVER() are no-op pass-through macros
3598     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3599     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3600     **    }else{
3601     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3602     **    }
3603     */
3604     case SQLITE_TESTCTRL_ALWAYS: {
3605       int x = va_arg(ap,int);
3606       rc = ALWAYS(x);
3607       break;
3608     }
3609 
3610     /*
3611     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3612     **
3613     ** The integer returned reveals the byte-order of the computer on which
3614     ** SQLite is running:
3615     **
3616     **       1     big-endian,    determined at run-time
3617     **      10     little-endian, determined at run-time
3618     **  432101     big-endian,    determined at compile-time
3619     **  123410     little-endian, determined at compile-time
3620     */
3621     case SQLITE_TESTCTRL_BYTEORDER: {
3622       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3623       break;
3624     }
3625 
3626     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3627     **
3628     ** Set the nReserve size to N for the main database on the database
3629     ** connection db.
3630     */
3631     case SQLITE_TESTCTRL_RESERVE: {
3632       sqlite3 *db = va_arg(ap, sqlite3*);
3633       int x = va_arg(ap,int);
3634       sqlite3_mutex_enter(db->mutex);
3635       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3636       sqlite3_mutex_leave(db->mutex);
3637       break;
3638     }
3639 
3640     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3641     **
3642     ** Enable or disable various optimizations for testing purposes.  The
3643     ** argument N is a bitmask of optimizations to be disabled.  For normal
3644     ** operation N should be 0.  The idea is that a test program (like the
3645     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3646     ** with various optimizations disabled to verify that the same answer
3647     ** is obtained in every case.
3648     */
3649     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3650       sqlite3 *db = va_arg(ap, sqlite3*);
3651       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3652       break;
3653     }
3654 
3655 #ifdef SQLITE_N_KEYWORD
3656     /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
3657     **
3658     ** If zWord is a keyword recognized by the parser, then return the
3659     ** number of keywords.  Or if zWord is not a keyword, return 0.
3660     **
3661     ** This test feature is only available in the amalgamation since
3662     ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
3663     ** is built using separate source files.
3664     */
3665     case SQLITE_TESTCTRL_ISKEYWORD: {
3666       const char *zWord = va_arg(ap, const char*);
3667       int n = sqlite3Strlen30(zWord);
3668       rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
3669       break;
3670     }
3671 #endif
3672 
3673     /* sqlite3_test_control(SQLITE_TESTCTRL_SCRATCHMALLOC, sz, &pNew, pFree);
3674     **
3675     ** Pass pFree into sqlite3ScratchFree().
3676     ** If sz>0 then allocate a scratch buffer into pNew.
3677     */
3678     case SQLITE_TESTCTRL_SCRATCHMALLOC: {
3679       void *pFree, **ppNew;
3680       int sz;
3681       sz = va_arg(ap, int);
3682       ppNew = va_arg(ap, void**);
3683       pFree = va_arg(ap, void*);
3684       if( sz ) *ppNew = sqlite3ScratchMalloc(sz);
3685       sqlite3ScratchFree(pFree);
3686       break;
3687     }
3688 
3689     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3690     **
3691     ** If parameter onoff is non-zero, configure the wrappers so that all
3692     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3693     ** undo this setting.
3694     */
3695     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3696       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3697       break;
3698     }
3699 
3700     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3701     **
3702     ** Set or clear a flag that indicates that the database file is always well-
3703     ** formed and never corrupt.  This flag is clear by default, indicating that
3704     ** database files might have arbitrary corruption.  Setting the flag during
3705     ** testing causes certain assert() statements in the code to be activated
3706     ** that demonstrat invariants on well-formed database files.
3707     */
3708     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3709       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3710       break;
3711     }
3712 
3713 
3714     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
3715     **
3716     ** Set the VDBE coverage callback function to xCallback with context
3717     ** pointer ptr.
3718     */
3719     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
3720 #ifdef SQLITE_VDBE_COVERAGE
3721       typedef void (*branch_callback)(void*,int,u8,u8);
3722       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
3723       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
3724 #endif
3725       break;
3726     }
3727 
3728     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
3729     case SQLITE_TESTCTRL_SORTER_MMAP: {
3730       sqlite3 *db = va_arg(ap, sqlite3*);
3731       db->nMaxSorterMmap = va_arg(ap, int);
3732       break;
3733     }
3734 
3735     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
3736     **
3737     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
3738     ** not.
3739     */
3740     case SQLITE_TESTCTRL_ISINIT: {
3741       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
3742       break;
3743     }
3744 
3745     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
3746     **
3747     ** This test control is used to create imposter tables.  "db" is a pointer
3748     ** to the database connection.  dbName is the database name (ex: "main" or
3749     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
3750     ** or off.  "tnum" is the root page of the b-tree to which the imposter
3751     ** table should connect.
3752     **
3753     ** Enable imposter mode only when the schema has already been parsed.  Then
3754     ** run a single CREATE TABLE statement to construct the imposter table in
3755     ** the parsed schema.  Then turn imposter mode back off again.
3756     **
3757     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
3758     ** the schema to be reparsed the next time it is needed.  This has the
3759     ** effect of erasing all imposter tables.
3760     */
3761     case SQLITE_TESTCTRL_IMPOSTER: {
3762       sqlite3 *db = va_arg(ap, sqlite3*);
3763       sqlite3_mutex_enter(db->mutex);
3764       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
3765       db->init.busy = db->init.imposterTable = va_arg(ap,int);
3766       db->init.newTnum = va_arg(ap,int);
3767       if( db->init.busy==0 && db->init.newTnum>0 ){
3768         sqlite3ResetAllSchemasOfConnection(db);
3769       }
3770       sqlite3_mutex_leave(db->mutex);
3771       break;
3772     }
3773   }
3774   va_end(ap);
3775 #endif /* SQLITE_OMIT_BUILTIN_TEST */
3776   return rc;
3777 }
3778 
3779 /*
3780 ** This is a utility routine, useful to VFS implementations, that checks
3781 ** to see if a database file was a URI that contained a specific query
3782 ** parameter, and if so obtains the value of the query parameter.
3783 **
3784 ** The zFilename argument is the filename pointer passed into the xOpen()
3785 ** method of a VFS implementation.  The zParam argument is the name of the
3786 ** query parameter we seek.  This routine returns the value of the zParam
3787 ** parameter if it exists.  If the parameter does not exist, this routine
3788 ** returns a NULL pointer.
3789 */
3790 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3791   if( zFilename==0 || zParam==0 ) return 0;
3792   zFilename += sqlite3Strlen30(zFilename) + 1;
3793   while( zFilename[0] ){
3794     int x = strcmp(zFilename, zParam);
3795     zFilename += sqlite3Strlen30(zFilename) + 1;
3796     if( x==0 ) return zFilename;
3797     zFilename += sqlite3Strlen30(zFilename) + 1;
3798   }
3799   return 0;
3800 }
3801 
3802 /*
3803 ** Return a boolean value for a query parameter.
3804 */
3805 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
3806   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3807   bDflt = bDflt!=0;
3808   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
3809 }
3810 
3811 /*
3812 ** Return a 64-bit integer value for a query parameter.
3813 */
3814 sqlite3_int64 sqlite3_uri_int64(
3815   const char *zFilename,    /* Filename as passed to xOpen */
3816   const char *zParam,       /* URI parameter sought */
3817   sqlite3_int64 bDflt       /* return if parameter is missing */
3818 ){
3819   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3820   sqlite3_int64 v;
3821   if( z && sqlite3DecOrHexToI64(z, &v)==SQLITE_OK ){
3822     bDflt = v;
3823   }
3824   return bDflt;
3825 }
3826 
3827 /*
3828 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
3829 */
3830 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
3831   int i;
3832   for(i=0; i<db->nDb; i++){
3833     if( db->aDb[i].pBt
3834      && (zDbName==0 || sqlite3StrICmp(zDbName, db->aDb[i].zName)==0)
3835     ){
3836       return db->aDb[i].pBt;
3837     }
3838   }
3839   return 0;
3840 }
3841 
3842 /*
3843 ** Return the filename of the database associated with a database
3844 ** connection.
3845 */
3846 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
3847   Btree *pBt;
3848 #ifdef SQLITE_ENABLE_API_ARMOR
3849   if( !sqlite3SafetyCheckOk(db) ){
3850     (void)SQLITE_MISUSE_BKPT;
3851     return 0;
3852   }
3853 #endif
3854   pBt = sqlite3DbNameToBtree(db, zDbName);
3855   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
3856 }
3857 
3858 /*
3859 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
3860 ** no such database exists.
3861 */
3862 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
3863   Btree *pBt;
3864 #ifdef SQLITE_ENABLE_API_ARMOR
3865   if( !sqlite3SafetyCheckOk(db) ){
3866     (void)SQLITE_MISUSE_BKPT;
3867     return -1;
3868   }
3869 #endif
3870   pBt = sqlite3DbNameToBtree(db, zDbName);
3871   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
3872 }
3873 
3874 #ifdef SQLITE_ENABLE_SNAPSHOT
3875 /*
3876 ** Obtain a snapshot handle for the snapshot of database zDb currently
3877 ** being read by handle db.
3878 */
3879 int sqlite3_snapshot_get(
3880   sqlite3 *db,
3881   const char *zDb,
3882   sqlite3_snapshot **ppSnapshot
3883 ){
3884   int rc = SQLITE_ERROR;
3885 #ifndef SQLITE_OMIT_WAL
3886   int iDb;
3887 
3888 #ifdef SQLITE_ENABLE_API_ARMOR
3889   if( !sqlite3SafetyCheckOk(db) ){
3890     return SQLITE_MISUSE_BKPT;
3891   }
3892 #endif
3893   sqlite3_mutex_enter(db->mutex);
3894 
3895   iDb = sqlite3FindDbName(db, zDb);
3896   if( iDb==0 || iDb>1 ){
3897     Btree *pBt = db->aDb[iDb].pBt;
3898     if( 0==sqlite3BtreeIsInTrans(pBt) ){
3899       rc = sqlite3BtreeBeginTrans(pBt, 0);
3900       if( rc==SQLITE_OK ){
3901         rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
3902       }
3903     }
3904   }
3905 
3906   sqlite3_mutex_leave(db->mutex);
3907 #endif   /* SQLITE_OMIT_WAL */
3908   return rc;
3909 }
3910 
3911 /*
3912 ** Open a read-transaction on the snapshot idendified by pSnapshot.
3913 */
3914 int sqlite3_snapshot_open(
3915   sqlite3 *db,
3916   const char *zDb,
3917   sqlite3_snapshot *pSnapshot
3918 ){
3919   int rc = SQLITE_ERROR;
3920 #ifndef SQLITE_OMIT_WAL
3921 
3922 #ifdef SQLITE_ENABLE_API_ARMOR
3923   if( !sqlite3SafetyCheckOk(db) ){
3924     return SQLITE_MISUSE_BKPT;
3925   }
3926 #endif
3927   sqlite3_mutex_enter(db->mutex);
3928   if( db->autoCommit==0 ){
3929     int iDb;
3930     iDb = sqlite3FindDbName(db, zDb);
3931     if( iDb==0 || iDb>1 ){
3932       Btree *pBt = db->aDb[iDb].pBt;
3933       if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
3934         rc = sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), pSnapshot);
3935         if( rc==SQLITE_OK ){
3936           rc = sqlite3BtreeBeginTrans(pBt, 0);
3937           sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), 0);
3938         }
3939       }
3940     }
3941   }
3942 
3943   sqlite3_mutex_leave(db->mutex);
3944 #endif   /* SQLITE_OMIT_WAL */
3945   return rc;
3946 }
3947 
3948 /*
3949 ** Free a snapshot handle obtained from sqlite3_snapshot_get().
3950 */
3951 void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
3952   sqlite3_free(pSnapshot);
3953 }
3954 #endif /* SQLITE_ENABLE_SNAPSHOT */
3955